COT - Certified Ophthalmic Technician Exam — Questions and Answers

Question 1: A patient suffers an ischemic stroke affecting the right optic tract. On swinging flashlight test, which eye is most likely to demonstrate a relative afferent pupillary defect (RAPD), and why?

Both eyes equally — the tract carries fibers from both eyes symmetrically
Right eye — the ipsilateral eye always shows RAPD in optic tract lesions
Neither eye — optic tract lesions are post-geniculate and no longer influence the pupillary reflex arc
Left eye — nasal retinal fibers (which cross at the chiasm into the right tract) outnumber temporal fibers, so the left eye sustains greater total fiber loss (Correct answer)

Correct answer: Left eye — nasal retinal fibers (which cross at the chiasm into the right tract) outnumber temporal fibers, so the left eye sustains greater total fiber loss

The right optic tract carries temporal fibers from the right eye and nasal fibers from the left eye. Because nasal retinal fibers (approximately 53% of total) outnumber temporal fibers (approximately 47%), a right optic tract lesion destroys more fibers originating from the left eye than from the right. This asymmetry results in a RAPD in the left eye — contralateral to the lesion and ipsilateral to the hemianopic field loss. This is one of the rare situations where RAPD and the field defect localize to the same eye.

Question 2: A patient has a central corneal thickness of 620 µm. How does this affect Goldmann IOP readings compared to a 545 µm cornea?

IOP reading is unaffected
IOP reading is accurate only with correction tables
IOP reading is falsely high (Correct answer)
IOP reading is falsely low

Correct answer: IOP reading is falsely high

Thicker corneas resist applanation more, causing the Goldmann tonometer to overestimate true IOP.

Question 3: After instilling fluorescein for Goldmann tonometry, the mire semicircles appear very wide and thick. The technician should:

Ask the patient to blink to thin the tear film before retaking the reading (Correct answer)
Increase the force dial immediately
Record the reading as is since mire width does not matter
Switch to non-contact tonometry

Correct answer: Ask the patient to blink to thin the tear film before retaking the reading

Excess fluorescein causes wide mires that make the endpoint harder to judge accurately; having the patient blink redistributes and thins the tear film.

Question 4: Pantoscopic tilt of a spectacle frame refers to:

The curvature of the frame front in the horizontal plane (face-form wrap)
The inward angle of the temples wrapping around the head
The vertical forward tilt of the lens plane, with the bottom of the lenses closer to the cheeks than the top (Correct answer)
The horizontal rotation of the frame front on the face

Correct answer: The vertical forward tilt of the lens plane, with the bottom of the lenses closer to the cheeks than the top

Pantoscopic tilt is the vertical angle of the spectacle lens plane relative to the face — ideally 8–12° — with the lower edge of the lenses tilted toward the cheeks. This aligns the optical axis of the lens with the natural downward gaze direction used for reading.

Question 5: A neonate presents on day 3 of life with bilateral chemosis, copious mucopurulent discharge, and marked eyelid edema. Gram stain shows gram-negative intracellular diplococci. The mother received standard prenatal care but reported a penicillin allergy. The neonatologist notes the infant did not receive standard ocular prophylaxis at birth due to a protocol error. Which statement about the prophylaxis that was omitted is most accurate?

Silver nitrate 1% drops remain the standard of care in the US because they are bactericidal to both Neisseria gonorrhoeae and Chlamydia trachomatis equally
Povidone-iodine 2.5% has replaced erythromycin as the preferred prophylaxis due to superior coverage of both bacterial and chlamydial neonatal conjunctivitis
Tetracycline 1% ointment is the WHO-preferred prophylaxis and the CDC considers it interchangeable with erythromycin for all causative organisms
Erythromycin 0.5% ophthalmic ointment is the current CDC-recommended prophylaxis and reduces gonococcal ophthalmia neonatorum risk, though it does not reliably prevent chlamydial conjunctivitis (Correct answer)

Correct answer: Erythromycin 0.5% ophthalmic ointment is the current CDC-recommended prophylaxis and reduces gonococcal ophthalmia neonatorum risk, though it does not reliably prevent chlamydial conjunctivitis

Erythromycin 0.5% ophthalmic ointment is the only neonatal ocular prophylaxis currently approved by the FDA and recommended in the US (CDC/AAP guidelines). It is effective against Neisseria gonorrhoeae but has limited efficacy against Chlamydia trachomatis — neonates born to mothers with chlamydial infection still require systemic oral erythromycin treatment even after prophylaxis. Silver nitrate 1% was historically used but was discontinued in the US due to chemical conjunctivitis and lack of chlamydial coverage. Povidone-iodine 2.5% is used in some countries but is not FDA-approved for this indication in the US. Tetracycline ointment is a WHO alternative but is not considered interchangeable in current US guidelines for chlamydial coverage.

Question 6: In a supplemental testing context, what is the PRIMARY purpose of maintaining a chain of custody log for test materials?

To track how many students have used each version of the test
To allow instructors to review which questions students found most difficult
To ensure test materials have not been tampered with or accessed by unauthorized individuals (Correct answer)
To document the time each student spent on the exam for scheduling purposes

Correct answer: To ensure test materials have not been tampered with or accessed by unauthorized individuals

A chain of custody log documents who handled test materials, when, and under what conditions, which is critical for maintaining test security and integrity. It protects against unauthorized access or tampering. Tracking question difficulty or scheduling information are secondary concerns unrelated to the security purpose of a chain of custody.

Question 7: When a surgeon requests intracameral preservative-free lidocaine during cataract surgery, the technician draws it from a single-use vial because:

Preserved formulations are toxic to corneal endothelium (Correct answer)
Multi-dose vials cannot be opened on the sterile field
Preservatives increase viscosity, blocking phaco aspiration
Preserved lidocaine causes pupil dilation

Correct answer: Preserved formulations are toxic to corneal endothelium

Benzalkonium chloride and other preservatives are cytotoxic to corneal endothelial cells; only preservative-free preparations are safe for intracameral injection.

Question 8: When measuring monocular pupillary distances (PDs) for a progressive addition lens prescription, the technician measures the distance from the center of each pupil to:

The inner canthus of the opposite eye
The outer canthus of the same eye
The center of the nose bridge (midline) (Correct answer)
The center of the bridge of the frame

Correct answer: The center of the nose bridge (midline)

Monocular PD is measured from the center of each pupil to the midline (center of the nose). This gives a right PD and a left PD separately, which is critical for progressive lenses where optical centers must be precisely aligned to each pupil independently.

Question 9: During an FDA-approved clinical trial using an investigational ophthalmic imaging device, a patient asks the COT: 'Is this the same machine the clinic normally uses?' The COT knows the device is pre-market and not commercially available. What is the COT's correct course of action?

Avoid confirming or denying the device's regulatory status to prevent undue influence on the patient's willingness to participate
Honestly tell the patient the device is investigational and not yet commercially available, and offer to connect them with the principal investigator for further questions (Correct answer)
Defer entirely and say, 'You'll need to ask the doctor about equipment'
Reassure the patient that all devices in the clinic meet FDA standards and redirect them to the consent form they already signed

Correct answer: Honestly tell the patient the device is investigational and not yet commercially available, and offer to connect them with the principal investigator for further questions

Federal regulations governing human subjects research (45 CFR Part 46, FDA 21 CFR Part 50) require that research participants be kept truthfully informed and have their questions answered at any time. Deflecting or obscuring the investigational status of a device undermines informed consent—a fundamental ethical obligation. The COT must answer honestly and facilitate access to the principal investigator for detailed questions.

Question 10: Your ophthalmology practice receives a subpoena duces tecum from an attorney representing the plaintiff in a personal injury lawsuit, demanding the complete medical records of a current patient. The patient has not provided a signed HIPAA authorization. The office manager instructs staff to immediately copy and send all records. What is the correct response?

Comply immediately — a subpoena is a legal mandate that supersedes HIPAA's privacy protections
Release only records that are directly relevant to the injury, applying the minimum necessary standard before sending
Refuse to release any records until the patient provides a signed HIPAA authorization form
Contact the practice's legal counsel before releasing any records, as an attorney-issued subpoena does not automatically constitute a court order under HIPAA (Correct answer)

Correct answer: Contact the practice's legal counsel before releasing any records, as an attorney-issued subpoena does not automatically constitute a court order under HIPAA

This is a critical HIPAA distinction: a subpoena issued by an attorney is NOT the same as a court order signed by a judge. Under 45 CFR 164.512(e), a covered entity may disclose records in response to a subpoena only after receiving satisfactory assurance that the patient was notified and given an opportunity to object, or that a qualified protective order is in place. Automatically complying without legal review risks a HIPAA violation. Legal counsel must evaluate whether the subpoena meets HIPAA's conditions before any release.

Question 11: Vertex distance becomes clinically significant when a patient's spectacle prescription exceeds approximately:

±1.00 D
±4.00 D (Correct answer)
±8.00 D
±2.00 D

Correct answer: ±4.00 D

Vertex distance (the distance from the back surface of the spectacle lens to the front of the cornea) must be accounted for in prescriptions of approximately ±4.00 D or greater. At higher powers, even a few millimeters of difference in vertex distance changes the effective power of the lens reaching the eye.

Question 12: A patient with 20/20 acuity complains of glare and halos at night after LASIK. These symptoms are most likely caused by:

Increased IOP
Posterior capsule opacification
Ablation zone smaller than scotopic pupil diameter (Correct answer)
Residual refractive error

Correct answer: Ablation zone smaller than scotopic pupil diameter

When the scotopic (night) pupil dilates beyond the laser ablation zone, untreated peripheral cornea causes optical aberrations including halos and glare.

Question 13: A COT is performing a cycloplegic refraction on a 6-year-old. The cycloplegic agent has been instilled and 45 minutes have passed. The pupil is dilated but the patient can still accommodate 2 diopters. What is the most appropriate next step?

Proceed with refraction, as residual accommodation is clinically insignificant
Instill an additional drop of the cycloplegic agent and wait another 20–30 minutes (Correct answer)
Switch to a miotic agent to reverse the effect and restart
Document the finding and refer to the ophthalmologist for adult refraction technique

Correct answer: Instill an additional drop of the cycloplegic agent and wait another 20–30 minutes

Adequate cycloplegia requires the elimination of accommodation (typically less than 0.50 D residual). If 2 diopters of accommodation remain after the standard waiting period, cycloplegia is incomplete. The correct response is to instill an additional drop and wait longer before refracting, ensuring accurate measurement of the true refractive error.

Question 14: Specular microscopy reveals an endothelial cell density of 1,850 cells/mm², a coefficient of variation (CV) of 42%, and a hexagonality of 48%. A patient with these findings is scheduled for phacoemulsification. Which statement MOST accurately describes the surgical risk?

Cell density alone is within a safe range; the procedure carries standard risk
Hexagonality below 50% is the primary contraindication and the surgery should be postponed indefinitely
Elevated CV and low hexagonality indicate pleomorphism and polymegethism, suggesting cell stress that increases risk of decompensation beyond what density alone predicts (Correct answer)
The CV of 42% is within normal limits and only hexagonality needs to be addressed before surgery

Correct answer: Elevated CV and low hexagonality indicate pleomorphism and polymegethism, suggesting cell stress that increases risk of decompensation beyond what density alone predicts

Normal endothelial morphology includes CV < 30% (polymegethism index) and hexagonality > 60%. A CV of 42% indicates significant cell size variability (polymegethism), and hexagonality of 48% indicates poor cell shape regularity (pleomorphism). These morphological abnormalities reflect a stressed endothelium that is less capable of compensating for surgical trauma, even if the absolute cell count (1,850 cells/mm²) is still above the critical decompensation threshold (~500–700 cells/mm²). The combination of poor morphology with borderline-adequate density substantially elevates the risk of postoperative corneal edema and decompensation beyond what density alone would predict.

Question 15: A stool culture from a patient with bloody diarrhea grows a colorless colony on MacConkey agar that is sorbitol-negative. Further testing confirms the organism is O157:H7 serotype. Which virulence mechanism is PRIMARILY responsible for the life-threatening complication of hemolytic uremic syndrome (HUS)?

Invasion of the intestinal epithelium causing direct tissue destruction
Formation of biofilm that obstructs renal tubules
Production of Shiga toxin that damages renal endothelial cells (Correct answer)
Release of exotoxin A that inhibits protein synthesis in hepatocytes

Correct answer: Production of Shiga toxin that damages renal endothelial cells

E. coli O157:H7 produces Shiga toxins (Stx1 and Stx2), which are absorbed into the bloodstream and bind to Gb3 receptors on renal glomerular endothelial cells. The toxin inhibits protein synthesis by inactivating the 60S ribosomal subunit, causing endothelial cell death, platelet aggregation, and the triad of HUS: microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure.

Question 16: When performing A-scan on a silicone oil-filled eye, the technician must:

Use a silicone-specific velocity setting (~980 m/s) (Correct answer)
Avoid A-scan entirely
Use a higher gain setting
Use the standard vitreous velocity

Correct answer: Use a silicone-specific velocity setting (~980 m/s)

Silicone oil has a much lower sound velocity (~980 m/s) than vitreous, requiring adjustment to avoid axial length errors.

Question 17: Which visual field defect pattern is most characteristic of a lesion in the parietal lobe optic radiations?

Superior homonymous quadrantanopia ('pie on the floor') (Correct answer)
Cecocentral scotoma
Bitemporal hemianopia
Inferior homonymous quadrantanopia ('pie in the sky')

Correct answer: Superior homonymous quadrantanopia ('pie on the floor')

Parietal lobe lesions damage the superior optic radiations, producing a contralateral inferior homonymous quadrantanopia (superior fibers run through the parietal lobe).

Question 18: Which is the best knife for making a clear corneal tunnel in phacoemulsification?

Titanium knife
Diamond knife (Correct answer)
Stainless steel knife
Brass coated knife

Correct answer: Diamond knife

Diamond is the strongest material on earth and knives made from diamond are sharp and help in making a precise corneal tunnel. Knives made from other materials are relatively less sharp and can give rise to ragged edges.

Question 19: During enucleation surgery, an orbital implant is placed after globe removal. The technician should prepare which material most commonly used for modern orbital implants?

Porous polyethylene (Medpor) or hydroxyapatite (Correct answer)
Titanium mesh plate
PMMA acrylic sphere
Silicone solid sphere

Correct answer: Porous polyethylene (Medpor) or hydroxyapatite

Porous polyethylene and hydroxyapatite are favored because fibrovascular ingrowth allows direct pegging and superior prosthetic motility.

Question 20: A technician is preparing a patient for a Goldmann visual field test. Which of the following describes the stimulus presentation method used in this type of perimetry?

A grid of vertical bars that flicker at varying rates.
Static stimuli of varying brightness presented at fixed locations.
An electrical signal measurement from the retina in response to flashing lights.
A moving light stimulus of a set size and intensity brought from non-seeing to seeing areas. (Correct answer)

Correct answer: A moving light stimulus of a set size and intensity brought from non-seeing to seeing areas.

Goldmann perimetry is the primary example of kinetic perimetry. In this method, a light stimulus of a specific size and brightness is moved from the periphery of the visual field toward the center until the patient indicates they can see it. This process maps out isopters, or areas of equal retinal sensitivity.

Question 21: A COT student is reviewing a culture of a strict anaerobe isolated from a deep wound infection. The organism produces black colonies on Bacteroides bile esculin (BBE) agar, is resistant to kanamycin and vancomycin, but sensitive to colistin. It also produces a unique enzyme that degrades heparin. Which species BEST fits this profile?

Prevotella melaninogenica
Bacteroides fragilis
Fusobacterium nucleatum
Porphyromonas gingivalis (Correct answer)

Correct answer: Porphyromonas gingivalis

Porphyromonas gingivalis produces black-pigmented colonies on BBE agar due to heme accumulation, is resistant to kanamycin and vancomycin (key Bacteroidetes traits) but sensitive to colistin, distinguishing it from Bacteroides fragilis (colistin resistant). Crucially, P. gingivalis produces a heparanase that degrades heparin — a virulence factor linked to periodontal tissue invasion. Prevotella melaninogenica also produces pigment but is colistin sensitive AND kanamycin sensitive. Fusobacterium does not produce black pigment on BBE.

Question 22: Under OSHA's Bloodborne Pathogen Standard, which of the following is the ophthalmic practice's PRIMARY obligation following a needlestick injury to a COT?

Require the employee to cover the cost of post-exposure prophylaxis from their health insurance
Notify the state health department within 24 hours and quarantine the exposed area
File an incident report within 30 days and offer the employee optional HIV testing
Immediately document the exposure and provide the employee with a confidential medical evaluation at no cost (Correct answer)

Correct answer: Immediately document the exposure and provide the employee with a confidential medical evaluation at no cost

OSHA's Bloodborne Pathogen Standard requires employers to immediately document the exposure incident and provide the affected employee with a confidential medical evaluation and follow-up at no cost to the employee. This includes testing, counseling, and post-exposure prophylaxis if indicated.

Question 23: During a retrobulbar block administered immediately before strabismus surgery, the patient develops sudden onset of bradycardia, hypotension, and loss of consciousness 30 seconds after injection. The MOST probable mechanism and the technician's FIRST priority action are:

Oculocardiac reflex triggered by globe compression; prepare atropine and alert anesthesia
Vasovagal syncope from anxiety; recline the patient and monitor oxygen saturation
Brainstem anesthesia from inadvertent intradural injection; call a code and support airway/circulation (Correct answer)
Anaphylaxis to the local anesthetic; administer epinephrine 0.3 mg IM and prepare for intubation

Correct answer: Brainstem anesthesia from inadvertent intradural injection; call a code and support airway/circulation

Rapid loss of consciousness combined with cardiovascular collapse within 30 seconds of retrobulbar injection is the classic presentation of brainstem anesthesia (also called 'brainstem spread'). It occurs when the needle enters the optic nerve sheath and anesthetic tracks centrally through the subdural/subarachnoid space to the brainstem. This is a rare but immediately life-threatening emergency. The oculocardiac reflex occurs during traction on extraocular muscles, not from injection. Vasovagal syncope does not cause the rapid, severe hemodynamic collapse described. Anaphylaxis to amides is extremely rare and presents differently. The technician's first priority is to call an emergency code and support airway and circulation immediately.

Question 24: A confrontation visual field test is considered:

A gross screening test that detects large field defects but misses subtle losses (Correct answer)
The gold standard for glaucoma monitoring
The preferred method for mapping scotomas in neurological conditions
Equivalent to automated perimetry for detecting early disease

Correct answer: A gross screening test that detects large field defects but misses subtle losses

Confrontation testing is a quick clinical screening tool that reliably detects large hemianopias or quadrantanopias but lacks the sensitivity to identify early or subtle field defects.

Question 25: A technician is performing the Worth 4-Dot test on a patient. The patient, wearing red/green glasses (red lens over the right eye), reports seeing five dots (two red and three green). What does this result indicate?

Suppression of the right eye
Normal binocular fusion
Diplopia (double vision) (Correct answer)
Suppression of the left eye

Correct answer: Diplopia (double vision)

Seeing five dots (two red through the right eye and three green through the left eye) indicates that both eyes are seeing simultaneously but are not fusing the images, resulting in diplopia, or double vision. Normal fusion would result in seeing four dots. Suppression of one eye would lead to seeing only the dots visible to the non-suppressed eye (two red or three green).

Question 26: A technician performs Schiotz tonometry on a patient and obtains a scale reading of 4.0 using the 5.5 g weight. The conversion table gives an IOP of approximately 24 mmHg. However, the patient has a history of high myopia and scleral staphyloma. Why should this reading be interpreted with particular caution?

Scleral rigidity is decreased in high myopia and staphyloma, causing Schiotz tonometry to underestimate true IOP (Correct answer)
High myopia reduces aqueous humor production, making Schiotz values systematically low
The Schiotz plunger cannot seat properly on a myopic eye due to the flatter cornea
High myopes have thinner corneas that increase Schiotz scale displacement, falsely elevating the reading

Correct answer: Scleral rigidity is decreased in high myopia and staphyloma, causing Schiotz tonometry to underestimate true IOP

Schiotz tonometry is an indentation technique that displaces ocular volume. Its accuracy depends on ocular rigidity (the eye's resistance to deformation). Eyes with scleral staphyloma and high axial myopia have reduced scleral rigidity. A less rigid eye indents more easily, producing a higher scale reading for any given IOP — which the standard conversion table interprets as lower IOP. Thus Schiotz underestimates true IOP in low-rigidity eyes. This is a fundamental limitation that makes applanation tonometry preferable in such patients.

Question 27: When administering the Farnsworth-Munsell 100-Hue test to a patient with a suspected toxic maculopathy from hydroxychloroquine use, which error pattern would be MOST characteristic and diagnostically important?

A tritan-axis error pattern (errors concentrated along caps 46–70), indicating blue-yellow discrimination loss (Correct answer)
A deutan-axis error pattern (errors concentrated along caps 28–58 and 80–100)
A protan-axis error pattern (errors concentrated along caps 1–28 and 58–80)
Random, scattered errors throughout all 85 caps with no discernible axis

Correct answer: A tritan-axis error pattern (errors concentrated along caps 46–70), indicating blue-yellow discrimination loss

Hydroxychloroquine toxicity characteristically produces a tritan (blue-yellow) type of color vision loss in early stages, corresponding to damage to the short-wavelength-sensitive (S-cone) pathways predominantly affected by macular toxicity. Errors clustering along the tritan axis on the FM 100-Hue test are a sensitive early indicator of toxicity before structural changes appear on imaging. Protan and deutan patterns are more typical of hereditary red-green deficiencies.

Question 28: A patient reports a sudden painless loss of vision in one eye described as 'a curtain coming down.' This history is most consistent with:

Optic neuritis
Rhegmatogenous retinal detachment (Correct answer)
Vitreous hemorrhage
Central serous chorioretinopathy

Correct answer: Rhegmatogenous retinal detachment

A 'curtain' or 'shadow' descending over the visual field is the classic description of a rhegmatogenous retinal detachment as it progresses to involve the macula.

Question 29: Which OCT scan pattern provides the most comprehensive macular thickness map for detecting early diabetic macular edema?

Macular cube (raster) scan (Correct answer)
Radial spoke pattern
Circle scan around the optic disc
Single horizontal line scan

Correct answer: Macular cube (raster) scan

A macular cube (dense raster) scan samples the entire macular area with multiple parallel B-scans, providing a full thickness map.

Question 30: Which retinoscopy reflex motion indicates that the eye is corrected and the far point coincides with the examiner's peephole?

Against motion
With motion
Neutralization (no motion) (Correct answer)
Scissors motion

Correct answer: Neutralization (no motion)

Neutralization occurs when no movement of the reflex is seen, meaning the far point is at the examiner's working distance.

Question 31: Which cells in the trabecular meshwork are responsible for phagocytosis of debris in the aqueous outflow pathway?

Müller cells
Trabecular cells (Correct answer)
Endothelial cells
Schlemm's canal cells

Correct answer: Trabecular cells

Trabecular cells (trabecular meshwork cells) are phagocytic and help maintain outflow facility by clearing debris from the intertrabecular spaces.

Question 32: When visually inspecting a groove weld, the inspector finds that the root of the weld does not penetrate completely through the joint thickness. This condition is termed:

Root concavity
Incomplete joint penetration (IJP) (Correct answer)
Underfill
Shrinkage void

Correct answer: Incomplete joint penetration (IJP)

Incomplete joint penetration (IJP) occurs when the weld metal does not extend through the full thickness of the joint as required. Underfill refers to a depression in the weld face below the adjacent base metal surface, root concavity is a concave condition at the root surface, and a shrinkage void is a cavity formed by solidification shrinkage.

Question 33: A patient fitted with a rigid gas-permeable (RGP) lens shows fluorescein pooling in the midperiphery and bearing centrally. Which fitting relationship does this describe, and what is the likely consequence if left uncorrected?

Steep fit; risk of central corneal touch causing epithelial disruption and 3 o'clock/9 o'clock staining
Steep fit; risk of peripheral seal-off reducing tear exchange and causing central epithelial hypoxia (Correct answer)
Flat fit; risk of central corneal touch causing epithelial disruption and 3 o'clock/9 o'clock staining
Flat fit; risk of peripheral seal-off reducing tear exchange and causing central epithelial hypoxia

Correct answer: Steep fit; risk of peripheral seal-off reducing tear exchange and causing central epithelial hypoxia

A steep RGP fit shows a central fluorescein pool (lens vaults the cornea) with midperipheral bearing (where the lens contacts). This creates peripheral seal-off, dramatically reducing tear exchange beneath the lens, leading to hypoxia and potential central epithelial edema or scarring.

Question 34: A COT inspector is examining a fillet weld and notices that the weld metal has flowed over the toe of the weld onto the base metal without fusing to it. This discontinuity is called:

Excessive convexity
Incomplete fusion
Cold lap (overlap) (Correct answer)
Undercut

Correct answer: Cold lap (overlap)

Cold lap, also known as overlap, occurs when molten weld metal flows over the base metal at the toe of the weld but does not fuse to it, creating a notch-like condition. Undercut is a groove in the base metal, incomplete fusion refers to lack of bonding between weld passes or between weld and base metal internally, and excessive convexity means the weld face is too high above the base metal plane.

Question 35: Which instrument measures corneal curvature and is used to fit contact lenses?

Lensometer
Keratometer (Correct answer)
Tonometer
Pachymeter

Correct answer: Keratometer

The keratometer measures the radius of curvature of the anterior corneal surface, expressed in diopters or millimeters.

Question 36: Which notation system is used to document the status of the lens during slit-lamp examination?

Logmar scale
Humphrey scoring
Snellen notation
LOCS (Lens Opacities Classification System) (Correct answer)

Correct answer: LOCS (Lens Opacities Classification System)

The Lens Opacities Classification System (LOCS) provides a standardized grading scale for nuclear, cortical, and posterior subcapsular cataracts.

Question 37: Internuclear ophthalmoplegia (INO) is caused by a lesion in which structure?

Oculomotor nucleus
Abducens nucleus
Trochlear nucleus
Medial longitudinal fasciculus (Correct answer)

Correct answer: Medial longitudinal fasciculus

INO results from a lesion in the medial longitudinal fasciculus (MLF), disrupting conjugate horizontal gaze coordination between the abducens and contralateral oculomotor nuclei.

Question 38: A patient wearing high-Dk silicone hydrogel lenses presents with asymptomatic limbal redness confined to the superior limbus under the upper lid, absent at the inferior limbus, with normal corneal clarity. Slit-lamp exam reveals fine superior limbal injection and subtle papillary changes on the upper tarsal plate. Which condition is most consistent with these findings?

Hypoxic limbal neovascularization secondary to inadequate Dk/t despite silicone hydrogel material
Superior limbic keratoconjunctivitis (SLK) exacerbated by contact lens wear, likely requiring lens-free interval and topical treatment (Correct answer)
Contact lens-induced acute red eye (CLARE), requiring lens cessation for 2 weeks
Giant papillary conjunctivitis (GPC) Stage I, managed by increasing lens replacement frequency

Correct answer: Superior limbic keratoconjunctivitis (SLK) exacerbated by contact lens wear, likely requiring lens-free interval and topical treatment

The localized superior limbal injection that mirrors under-lid exposure, combined with superior tarsal papillary changes and asymptomatic presentation, is characteristic of SLK associated with contact lens wear. Unlike GPC (which primarily shows large papillae > 0.3 mm) or CLARE (acute red eye, often with discharge), SLK is a chronic mechanical/inflammatory condition at the superior limbus requiring a lens holiday and possibly topical treatments such as topical vitamin A or silver nitrate application by the physician.

Question 39: A surgical technician is preparing the back table for a trabeculectomy with adjunctive mitomycin-C (MMC). Which handling protocol is most critical from an ocular toxicity standpoint?

Mixing MMC in a sterile bowl on the back table and discarding unused solution into the scrub sink
Applying MMC sponges with titanium forceps and irrigating with BSS for exactly 30 seconds post-application
Timing MMC exposure for 5 minutes regardless of concentration to standardize bleb formation
Ensuring MMC-soaked sponges never contact the cut edge of the scleral flap and performing copious BSS irrigation before scleral flap suturing (Correct answer)

Correct answer: Ensuring MMC-soaked sponges never contact the cut edge of the scleral flap and performing copious BSS irrigation before scleral flap suturing

MMC is an antimetabolite that can cause severe avascular blebs, hypotony, and endophthalmitis if it contacts the wound edges or drains inadequately. The critical protocol is preventing MMC sponge contact with cut tissue edges and performing copious BSS lavage (at least 20–30 mL) before suturing. Disposing MMC in the scrub sink violates hazardous waste protocols; exposure time varies by surgeon/concentration; titanium vs. regular forceps is not the key safety point.

Question 40: During fluorescein angiography, a patient develops early hyperfluorescence that increases in intensity and size throughout the study but does not leak beyond the lesion boundary in the late frames. This pattern is most consistent with which finding?

Classic choroidal neovascularization
Window defect from RPE atrophy (Correct answer)
Occult choroidal neovascularization with fibrovascular PED
Retinal arterial macroaneurysm

Correct answer: Window defect from RPE atrophy

A window defect caused by RPE atrophy transmits background choroidal fluorescence, producing hyperfluorescence that brightens as the choroidal flush intensifies but fades symmetrically with the background and does not enlarge or leak beyond the lesion margin in late frames. Classic CNV leaks and expands; occult CNV shows late stippled leakage; macroaneurysms often show hypofluorescent halos or wall staining.

Question 41: During visual assessment of upper extremity function, a patient is asked to raise both arms overhead. You observe that the right scapula wings off the thorax during shoulder flexion above 90°. This finding MOST directly suggests weakness in which muscle?

Infraspinatus
Middle trapezius
Subscapularis
Serratus anterior (Correct answer)

Correct answer: Serratus anterior

Serratus anterior is the primary muscle responsible for holding the medial border of the scapula against the thoracic wall and for upwardly rotating the scapula during arm elevation. Weakness of the serratus anterior classically presents as 'winging' of the medial scapular border, which becomes most prominent during forward flexion or push-up movements. Middle trapezius weakness causes more of a downward rotation issue, not classic medial winging.

Question 42: A 16-year-old patient presents alone requesting a contact lens fitting. During the refraction, you notice signs consistent with early keratoconus. The patient begs you not to tell their parents because they fear being taken off contacts. Under HIPAA and minor consent law, what is the most appropriate action?

Refuse to document keratoconus findings until a parent or guardian is present to consent to the diagnostic workup
Document the findings, inform the supervising ophthalmologist immediately, and follow the practice's minor consent protocol — parental notification may be required for diagnosis and treatment decisions (Correct answer)
Proceed with the fitting and respect the minor's confidentiality request since contact lens fittings are elective
Notify the parents directly without informing the ophthalmologist, since keratoconus is a serious condition requiring urgent intervention

Correct answer: Document the findings, inform the supervising ophthalmologist immediately, and follow the practice's minor consent protocol — parental notification may be required for diagnosis and treatment decisions

Keratoconus is a progressive, potentially vision-threatening condition that constitutes a medical diagnosis requiring treatment decisions beyond the scope of a routine contact lens fitting. Most states do not allow minors to independently consent to medical treatment for conditions of this nature. The COT must escalate to the supervising ophthalmologist, who will determine the appropriate consent and disclosure pathway. Bypassing the physician (option D) or suppressing findings (option C) are ethically and legally untenable.

Question 43: When performing a Schirmer's test with anesthesia to measure basal tear secretion, which topical anesthetic is most appropriate and why?

Cocaine 4%, because it simultaneously blocks reflex tearing via sympathomimetic vasoconstriction of lacrimal gland vasculature
Oxybuprocaine 0.4%, because its pH is closest to tear film pH, avoiding chemical irritation that would trigger reflex tearing
Tetracaine 0.5%, because its longer duration of action ensures the patient feels no reflex tearing during the full 5-minute test
Proparacaine 0.5%, because it minimally disrupts goblet cell function compared to aminoester anesthetics (Correct answer)

Correct answer: Proparacaine 0.5%, because it minimally disrupts goblet cell function compared to aminoester anesthetics

Proparacaine (proxymetacaine) 0.5% is the standard anesthetic used for Schirmer's test with anesthesia (Schirmer's II or basic secretion test). It is preferred because it causes less epithelial toxicity and less disruption to goblet cells and the mucin layer than aminoester anesthetics like tetracaine, which at repeated doses can damage the corneal epithelium and alter tear film composition. The goal is to eliminate reflex tearing while preserving basal secretion measurements without introducing confounding chemical irritation. Cocaine causes vasoconstriction that would itself alter lacrimal gland output, making it unsuitable.

Question 44: During retinoscopy, if the examiner works at 67 cm, what working distance lens should be subtracted from the gross retinoscopy finding?

+2.00 D
+1.50 D (Correct answer)
+2.50 D
+1.00 D

Correct answer: +1.50 D

At 67 cm working distance, the vergence of light from that distance equals +1.50 D, which must be subtracted from the gross finding.

Question 45: During a visual assessment of a patient's gait, you notice the patient leans their trunk laterally toward the stance limb during the loading response phase. This compensatory pattern most likely indicates weakness in which muscle group?

Hip flexors on the swing side
Hip abductors on the stance side (Correct answer)
Ankle plantar flexors on the stance side
Knee extensors on the stance side

Correct answer: Hip abductors on the stance side

Lateral trunk lean toward the stance limb (Trendelenburg gait) is a compensatory strategy used when the hip abductors (primarily gluteus medius) are weak. By shifting the center of mass over the stance limb, the patient reduces the demand on the abductors to keep the pelvis level during single-limb support.

Question 46: A technician performs applanation A-scan biometry and obtains an axial length of 22.50 mm. The same eye is then measured using immersion A-scan, yielding a measurement of 22.85 mm. What is the most likely reason for this discrepancy?

Corneal compression from the applanation probe. (Correct answer)
Misalignment of the probe off the visual axis during applanation.
Incorrect sound velocity setting for the crystalline lens.
Patient blinking excessively during the immersion scan.

Correct answer: Corneal compression from the applanation probe.

Applanation (contact) biometry involves touching the ultrasound probe to the cornea, which can indent or compress it, artificially shortening the axial length measurement. [2, 4] Immersion biometry avoids corneal contact by using a saline-filled scleral shell, providing a more accurate and typically longer measurement. [2, 9] The difference of 0.2 mm to 0.3 mm is classic for this effect. [2]

Question 47: What does the term 'applanation' refer to in contact A-scan biometry?

Compressing the cornea with the probe (Correct answer)
Aligning the probe to the optic axis
Flooding the eye with saline
Dilating the pupil before measurement

Correct answer: Compressing the cornea with the probe

Applanation biometry involves the probe touching and slightly compressing the cornea, which can shorten axial length readings.

Question 48: In Heidelberg Retinal Tomography (HRT), the reference plane used to calculate neuroretinal rim area is set at:

The Bruch's membrane opening
The lamina cribrosa surface
The vitreoretinal interface
50 μm posterior to the temporal disc margin (Correct answer)

Correct answer: 50 μm posterior to the temporal disc margin

HRT uses a reference plane set 50 μm posterior to the mean height of the papillomacular bundle to calculate disc topography parameters.

Question 49: The corneal epithelium is replaced approximately every how many days under normal conditions?

5–7 days (Correct answer)
30–60 days
14–21 days
1–2 days

Correct answer: 5–7 days

The corneal epithelium completely renews itself approximately every 5–7 days, supplied by limbal stem cells at the corneal periphery.

Question 50: The superior oblique muscle is innervated by which cranial nerve?

CN III
CN V
CN VI
CN IV (Correct answer)

Correct answer: CN IV

Cranial nerve IV (trochlear nerve) innervates the superior oblique muscle, which intorts, depresses, and abducts the eye.

Question 51: Which of the following would cause a falsely LOW IOP reading with non-contact (air-puff) tonometry?

Excessive fluorescein instillation
Patient looking slightly downward (Correct answer)
Patient squeezing lids tightly
Edematous (waterlogged) cornea

Correct answer: Patient looking slightly downward

When the patient looks slightly downward, the air puff strikes the peripheral rather than central cornea, yielding an artificially low reading.

Question 52: Dipivefrin is a prodrug converted to which active compound after penetrating the cornea?

Epinephrine (Correct answer)
Timolol
Brimonidine
Pilocarpine

Correct answer: Epinephrine

Dipivefrin is a prodrug of epinephrine that is converted by corneal esterases after penetration, lowering IOP with fewer systemic side effects than direct epinephrine use.

Question 53: The mechanism by which latanoprost lowers intraocular pressure is primarily by:

Decreasing aqueous humor production by the ciliary body
Inhibiting carbonic anhydrase in the ciliary epithelium
Constricting the pupil to open the trabecular meshwork
Increasing uveoscleral outflow via prostaglandin FP receptor activation (Correct answer)

Correct answer: Increasing uveoscleral outflow via prostaglandin FP receptor activation

Latanoprost is a prostaglandin F2α analog that binds FP receptors in the ciliary muscle, increasing uveoscleral (unconventional) outflow to reduce IOP.

Question 54: A keratometry reading on the right eye yields K1 = 44.25 D @ 180° and K2 = 46.75 D @ 90°. When fitting a spherical rigid gas-permeable (RGP) contact lens, the technician follows the 'fit-on-K' rule. What base curve should be selected, and what type of tear lens will result?

Base curve 45.50 D; a neutralizing tear lens forms in both meridians
Base curve 46.75 D; a plus tear lens forms in both meridians
Base curve 44.25 D; a minus tear lens forms in the horizontal meridian and a plus tear lens in the vertical meridian
Base curve 44.25 D; a plus tear lens forms in the vertical meridian (Correct answer)

Correct answer: Base curve 44.25 D; a plus tear lens forms in the vertical meridian

Fitting 'on-K' for a spherical RGP means selecting the flatter K (44.25 D @ 180°). In the steeper vertical meridian (46.75 D), the cornea is steeper than the lens back surface, creating a pool of tears that forms a plus-powered tear lens. In the flat meridian the lens aligns with the cornea, producing a plano tear lens. The residual astigmatism equals the difference (2.50 D) and must be corrected by spectacles or a toric lens.

Question 55: The preferred retinal locus (PRL) is best described as:

The region of highest rod photoreceptor density
The fovea in a healthy, unaffected eye
A peripheral retinal area spontaneously adopted for fixation when the fovea is damaged (Correct answer)
The optic nerve head (blind spot)

Correct answer: A peripheral retinal area spontaneously adopted for fixation when the fovea is damaged

The PRL is a non-foveal retinal location that a patient with macular disease spontaneously develops as the new fixation point to optimize remaining vision.

Question 56: A patient with a −9.00 D prescription is switching from CR-39 lenses (Abbe value 58) to ultra-high-index 1.74 lenses (Abbe value 33) for cosmetic thinness. What visual side effect should the technician specifically counsel the patient about?

Noticeably increased color fringing and chromatic dispersion in peripheral gaze (Correct answer)
Improved contrast sensitivity from the higher refractive index material
Reduced spherical aberration because of the flatter base curve used in high-index designs
Reduced peripheral blur due to improved oblique astigmatic aberration correction

Correct answer: Noticeably increased color fringing and chromatic dispersion in peripheral gaze

The Abbe value (V-number) is inversely related to lateral chromatic aberration: lower Abbe = more color dispersion. CR-39 (V = 58) produces minimal chromatic fringing; a 1.74 high-index lens (V = 33) nearly doubles the chromatic aberration. At −9.00 D, significant peripheral prism magnifies this effect, causing visible rainbow or color-fringe artifacts when the patient looks through the lens edge. Abbe value does not affect oblique astigmatic aberration or spherical aberration directly. Patients switching from CR-39 to ultra-high-index materials frequently report this as a quality complaint.

Question 57: JCAHPO offers several subspecialty certifications that credential holders can earn in addition to their primary credential. Which of the following is NOT a subspecialty certification currently offered through JCAHPO?

Ophthalmic Surgical Assisting (OSA) subspecialty certification
Glaucoma (GL) subspecialty certification
Retinal Angiography (RA) subspecialty certification
Oculoplastic Surgery (OPS) subspecialty certification (Correct answer)

Correct answer: Oculoplastic Surgery (OPS) subspecialty certification

JCAHPO's subspecialty certification catalog includes Retinal Angiography (RA), Glaucoma (GL), Contact Lens (CL), Low Vision (LV), Ophthalmic Surgical Assisting (OSA), Uveitis (UV), and several others. Oculoplastic Surgery is not among JCAHPO's defined subspecialty certification pathways — while oculoplastics is a recognized ophthalmology subspecialty, JCAHPO has not established a dedicated credential in that area. Confusing subspecialty interest areas with credentialed pathways is a common advanced-level error.

Question 58: A patient with keratoconus is being fit with a rigid gas-permeable (RGP) lens. The fluorescein pattern shows central pooling with mid-peripheral bearing and edge lift. Which fitting relationship does this describe?

Apical clearance fit (Correct answer)
Three-point touch fit
Alignment fit
Apical touch fit

Correct answer: Apical clearance fit

Apical clearance (steep fit) is characterized by central fluorescein pooling (dye accumulates under the central lens where it vaults the cone), mid-peripheral bearing (darkened annular zone of lens-cornea contact), and peripheral edge lift. This is the classic steep-fitting pattern. Apical touch shows central bearing (dark center), and alignment shows a uniform green pattern across the central zone.

Question 59: In a Galilean telescope, the eyepiece (ocular) lens is:

A convex (plus) lens
A prism pair
A concave (minus) lens (Correct answer)
A plano (zero power) lens

Correct answer: A concave (minus) lens

A Galilean telescope uses a concave (minus) lens as the eyepiece and a convex (plus) lens as the objective, producing an erect, upright image without requiring inverting prisms.

Question 60: The choroidal watershed zone, an area particularly vulnerable to ischemia in conditions such as anterior ischemic optic neuropathy, is located between territories supplied by which two arterial systems?

Anterior ciliary arteries and posterior ciliary arteries
Medial and lateral posterior ciliary arteries (Correct answer)
Central retinal artery and posterior ciliary arteries
Ophthalmic artery branches and internal carotid perforators

Correct answer: Medial and lateral posterior ciliary arteries

The choroid is perfused by multiple posterior ciliary arteries (PCAs), typically medial and lateral divisions. The watershed zone lies between the terminal perfusion territories of the medial and lateral PCAs, creating a region of relatively poor collateral circulation. This zone, located in the peripapillary choroid and optic nerve head, is highly susceptible to ischemia when perfusion pressure drops, which is the mechanism underlying non-arteritic anterior ischemic optic neuropathy (NAION).

Question 61: A COT performs color vision testing on a patient with type 2 diabetes and documented mild non-proliferative diabetic retinopathy (NPDR). The Farnsworth D-15 test reveals errors along the tritan (blue-yellow) confusion axis. The patient reports a father who was color-blind. Which conclusion is MOST clinically appropriate?

The D-15 test lacks sufficient sensitivity to differentiate congenital from acquired color vision defects
The axis of confusion strongly matches the pattern expected from the inherited paternal defect
Diabetic retinopathy characteristically produces protan-axis errors, so an inherited defect is the better explanation
Acquired tritan-axis errors are a recognized feature of retinal/macular disease and the NPDR is the more likely etiology (Correct answer)

Correct answer: Acquired tritan-axis errors are a recognized feature of retinal/macular disease and the NPDR is the more likely etiology

Acquired color vision defects secondary to retinal and macular disease — including diabetic retinopathy — characteristically affect the tritan (blue-yellow) axis. Congenital color vision deficiencies are overwhelmingly red-green (protan or deutan) in nature and are X-linked recessive. The presence of retinal pathology and the tritan axis pattern together make the acquired etiology the most defensible interpretation, regardless of family history. The D-15 is sufficiently sensitive to detect these axis differences.

Question 62: During fluorescein angiography, a patient develops a 'blocking defect' that appears hypofluorescent in both early and late phases. Which of the following is the MOST likely cause?

Window defect from RPE atrophy overlying a drusen
Geographic atrophy of the retinal pigment epithelium
Subretinal hemorrhage from a choroidal neovascular membrane (Correct answer)
Late staining from a pigment epithelial detachment

Correct answer: Subretinal hemorrhage from a choroidal neovascular membrane

A blocking defect that is hypofluorescent in both early AND late phases indicates an opaque substance physically blocking the choroidal fluorescence from reaching the camera — subretinal hemorrhage is the classic example. Geographic atrophy and RPE atrophy over drusen produce window (transmission) defects that are hyperfluorescent. A PED typically shows early hyperfluorescence with late staining or pooling, not consistent blocking.

Question 63: Which visual field test strategy presents stimuli at threshold levels determined by prior responses, making it more efficient than full threshold testing?

SITA Standard (Correct answer)
Goldmann kinetic
Amsler grid
Confrontation testing

Correct answer: SITA Standard

SITA (Swedish Interactive Thresholding Algorithm) Standard uses statistical modeling to estimate thresholds faster than traditional full threshold strategies.

Question 64: During a standing visual assessment, a COT observes that a patient has a bilateral 'swayback' posture characterized by a posterior shift of the pelvis relative to the feet and an anterior shift of the thorax. Compared to an ideal plumb line alignment, where would you expect the patient's lumbar spine to fall?

Posterior to the plumb line with reduced lordosis or flexion (Correct answer)
Anterior to the plumb line with increased lordosis
Directly on the plumb line with no lumbar deviation
Anterior to the plumb line with reduced lordosis

Correct answer: Posterior to the plumb line with reduced lordosis or flexion

In swayback posture, the pelvis shifts posteriorly and the hips move forward in front of the plumb line, while the thorax shifts anteriorly. This creates a long, flat (or slightly flexed) lumbar curve — the lumbar spine falls posterior to the plumb line and lumbar lordosis is reduced, unlike in hyperlordosis where the lumbar spine is anterior with an increased curve.

Question 65: Strabismus surgery to treat esotropia most commonly involves which procedure?

Bilateral lateral rectus resection
Bilateral medial rectus recession (Correct answer)
Lateral rectus resection and medial rectus recession
Superior oblique tenotomy

Correct answer: Bilateral medial rectus recession

Bilateral medial rectus recession is the standard surgical approach for comitant esotropia, weakening the overacting adductors.

Question 66: What is the purpose of performing a Seidel test intraoperatively after corneal wound closure?

To assess endothelial cell density post-closure
To verify pupil dilation adequacy
To measure intraocular pressure after suturing
To detect aqueous humor leakage through the wound (Correct answer)

Correct answer: To detect aqueous humor leakage through the wound

The Seidel test uses fluorescein dye to identify aqueous leakage; a streaming green fluorescence indicates a wound leak requiring additional sutures.

Question 67: A technician uses a manual lensometer to neutralize an unknown spherical lens. The target mires come into sharp focus when the power wheel is set to -3.25 D. What does this measurement represent?

The prismatic power of the lens.
The equivalent spherical power.
The front vertex power of the lens.
The back vertex power of the lens. (Correct answer)

Correct answer: The back vertex power of the lens.

Standard manual lensometers are designed to measure the back vertex power, which is the effective power of the lens relative to the eye's position. This measurement is crucial for ensuring the patient receives the correct prescribed power when wearing the glasses.

Question 68: During ocular motility testing, you ask a patient to follow your target with both eyes to the right. This binocular, conjugate movement is referred to as:

Convergence
Dextroversion (Correct answer)
Sursumduction
Duction

Correct answer: Dextroversion

Versions are binocular eye movements where both eyes move in the same direction. Movement of both eyes to the right is specifically termed dextroversion. Ductions are monocular movements (one eye at a time). Convergence is the simultaneous inward movement of both eyes, and sursumduction is the upward movement of a single eye.

Question 69: During pupil examination, anisocoria that is greater in dim light suggests the abnormal pupil is:

The smaller pupil (sphincter paresis)
Neither pupil is abnormal
The larger pupil (dilator paresis) (Correct answer)
Both pupils equally affected

Correct answer: The larger pupil (dilator paresis)

Anisocoria greater in dim light (when dilation is expected) indicates the larger pupil cannot dilate, suggesting Horner syndrome (dilator paresis) on that side.

Question 70: During retinoscopy, a technician sweeps the streak and observes two bright bands that appear to split apart and then close toward each other — a 'scissor reflex.' Which condition is this finding MOST strongly associated with?

Accommodative spasm secondary to prolonged near work
Irregular corneal astigmatism such as keratoconus (Correct answer)
Simple myopic astigmatism with steep vertical meridian
High latent hyperopia with full accommodation

Correct answer: Irregular corneal astigmatism such as keratoconus

A scissor reflex indicates an irregular or distorted wavefront caused by irregular corneal astigmatism — classically keratoconus, but also corneal scarring or ectasia. Because the optical surface is non-uniform, the retinoscopic reflex cannot be cleanly neutralized in a single meridian; instead the light fans out in opposite directions. This finding should prompt keratometry and topography, not continued attempts to refract with a standard phoropter.

Question 71: Which sterilization method is MOST appropriate for ophthalmic surgical instruments with heat-sensitive components?

Ethylene oxide (EtO) gas sterilization (Correct answer)
Steam autoclave at 134°C
Boiling in distilled water for 10 minutes
Dry heat oven at 160°C for 2 hours

Correct answer: Ethylene oxide (EtO) gas sterilization

Ethylene oxide (EtO) gas sterilization achieves full sterilization at low temperatures (37–63°C), making it safe for heat-sensitive materials such as plastics, rubber, and certain instrument components that would be damaged by autoclaving or dry heat. Boiling does not achieve sterilization.

Question 72: During a busy clinic day, an ophthalmologist instructs the COT to instill a topical anesthetic and then perform a Goldmann applanation tonometry measurement independently, without the physician present. Which principle applies to this situation?

The COT must refuse because instilling drops is outside all technician scope of practice
The COT can proceed provided the patient gives verbal consent
The COT may proceed because tonometry is a standard technician task
The COT should act only within the legally defined scope of practice for the state and ensure physician supervision as required (Correct answer)

Correct answer: The COT should act only within the legally defined scope of practice for the state and ensure physician supervision as required

Scope of practice for ophthalmic technicians varies by state law. In many states, COTs can instill drops and perform tonometry under physician supervision or pursuant to a standing order. The COT must know the specific state regulations and ensure the level of supervision required by law is met — patient consent alone does not override scope-of-practice rules.

Question 73: Which contact lens-related complication is characterized by upper tarsal conjunctival changes resembling cobblestones?

Giant papillary conjunctivitis (Correct answer)
Corneal neovascularization
Contact lens-induced acute red eye
Superior limbic keratoconjunctivitis

Correct answer: Giant papillary conjunctivitis

Giant papillary conjunctivitis (GPC) produces large papillae (>0.3 mm) on the upper tarsal conjunctiva, often from lens deposits or mechanical irritation.

Question 74: A patient's new glasses sit too close to the eyelashes, causing discomfort. The correct adjustment to increase the distance between the lenses and the eyes is to:

Replace the frame with one that has a longer bridge
Increase the pantoscopic tilt by angling the bottom of the frame outward
Tighten both temples to pull the frame back on the head
Open the nose pads outward to push the frame away from the face (Correct answer)

Correct answer: Open the nose pads outward to push the frame away from the face

Adjusting the nose pads outward (increasing the pad spread) raises the frame higher and pushes it away from the face, increasing vertex distance and reducing contact with the eyelashes. This is the appropriate frame adjustment for glasses sitting too close to the eyes.

Question 75: A 7-year-old child presents with reduced vision in one eye. The cover-uncover test reveals no movement of either eye when covered or uncovered. What does this most likely indicate?

Alternating esotropia
Amblyopia without strabismus (Correct answer)
Manifest tropia with fixation preference
Intermittent exotropia

Correct answer: Amblyopia without strabismus

If there is no movement on the cover-uncover test, there is no manifest strabismus (tropia). Amblyopia can exist without strabismus — it may be caused by anisometropia or stimulus deprivation. The absence of eye movement on testing rules out a manifest deviation.

Question 76: A patient has a short axial length of 20.5 mm. Which IOL formula is most appropriate?

SRK II
Haigis with default constants
Holladay 2 or Hoffer Q (Correct answer)
SRK/T

Correct answer: Holladay 2 or Hoffer Q

Hoffer Q and Holladay 2 are preferred for short eyes (axial length <22 mm) to minimize prediction errors.

Question 77: In diabetic patients, which type of diabetic retinopathy is characterized by the growth of abnormal new blood vessels on the retinal surface or optic disc?

Proliferative diabetic retinopathy (Correct answer)
Clinically significant macular edema
Background (non-proliferative) diabetic retinopathy
Preproliferative diabetic retinopathy

Correct answer: Proliferative diabetic retinopathy

Proliferative diabetic retinopathy (PDR) is defined by neovascularization — abnormal new blood vessels growing on the retinal surface, optic disc, or into the vitreous. These fragile vessels can bleed, causing vitreous hemorrhage, or lead to tractional retinal detachment. PDR represents advanced, sight-threatening disease.

Question 78: A 58-year-old low vision patient requires a bioptic telescope for driving rehabilitation. The prescribing clinician is choosing between a Galilean and a Keplerian design at 6× magnification. Which statement BEST justifies the preferred design choice for this application?

Galilean telescopes are preferred because they can achieve higher magnification with fewer optical elements
Keplerian telescopes are preferred because their inverted image improves the patient's awareness of the blind spot
Keplerian telescopes are preferred because they provide superior image resolution and a wider field of view at high magnifications (Correct answer)
Galilean telescopes are preferred because they produce an erect image without requiring corrective prisms, reducing weight

Correct answer: Keplerian telescopes are preferred because they provide superior image resolution and a wider field of view at high magnifications

Keplerian (astronomical) telescopes are the design of choice for bioptic telescopes at magnifications above approximately 4×. They use a positive objective and positive ocular lens, producing an inverted intermediate image that is corrected by internal prisms (e.g., Porro or Schmidt). This yields superior image brightness, resolution, and field of view compared to Galilean designs. Galilean telescopes, while lighter and producing erect images without prisms, suffer from severely degraded field of view and image quality at magnifications above 3–4×, making them impractical for high-power bioptic use.

Question 79: Which of the following BEST describes the Haigis formula's approach to IOL calculation?

Uses corneal diameter and lens thickness
Uses three constants (a0, a1, a2) and measures ACD (Correct answer)
Uses only axial length and keratometry
Uses surgeon factor and axial length only

Correct answer: Uses three constants (a0, a1, a2) and measures ACD

The Haigis formula uses three lens constants and incorporates measured ACD to predict effective lens position.

Question 80: When fitting a patient for spectacles, the correct temple length provides support by:

Resting the temple tip on the top of the ear with no contact behind the ear
Bending at the ear level and resting on the mastoid bone behind the ear (Correct answer)
Curving tightly over the ear and pressing on the side of the head
Crossing directly behind the skull above both ears

Correct answer: Bending at the ear level and resting on the mastoid bone behind the ear

A properly fitted temple should bend at approximately the level of the top of the ear and rest along the side of the head, with the temple tip resting behind and below the ear on the mastoid area. This distributes weight properly and prevents the frame from sliding down.

Question 81: A patient with prior myopic LASIK presents for cataract pre-op evaluation. Standard Javal-Schiotz keratometry is performed to calculate IOL power. Which outcome most accurately describes the expected error and its clinical consequence?

Keratometry will overestimate corneal power, causing an underpowered IOL and a hyperopic postoperative refraction (Correct answer)
Keratometry will underestimate corneal power, causing an overpowered IOL and a myopic postoperative refraction
Keratometry will accurately reflect true corneal power if the measurement is repeated three times and averaged
Keratometry will be unaffected; LASIK reshapes only the stromal bed and does not alter surface reflectivity

Correct answer: Keratometry will overestimate corneal power, causing an underpowered IOL and a hyperopic postoperative refraction

Standard keratometry samples an annular ring (~3 mm zone), which is on the shoulder of the LASIK ablation — not the flattest central zone. Furthermore, the assumed refractive index of 1.3375 encodes a fixed anterior-to-posterior corneal curvature ratio that is disrupted by LASIK (which flattens the anterior surface while leaving the posterior unchanged). Both factors cause keratometry to report a HIGHER corneal power than actually exists. Plugging this inflated K into standard IOL formulas yields a weaker IOL than needed, resulting in a hyperopic surprise — one of the most clinically significant errors in post-refractive cataract surgery.

Question 82: In the sterile surgical field, if the ophthalmic technician suspects an instrument has been contaminated, what is the correct action?

Submerge it in the BSS irrigation bowl on the field
Notify the surgeon only if the procedure is nearly complete
Wipe it with a sterile gauze and continue use
Remove it from the field and replace it with a sterile instrument (Correct answer)

Correct answer: Remove it from the field and replace it with a sterile instrument

Any instrument suspected of contamination must be removed immediately and replaced to maintain sterile field integrity and prevent infection.

Question 83: Which ophthalmic preservative found in many multi-dose eye drop bottles is known to be toxic to the corneal epithelium with long-term use?

Sodium hyaluronate
Hydroxypropyl methylcellulose
Benzalkonium chloride (BAK) (Correct answer)
Sodium chloride

Correct answer: Benzalkonium chloride (BAK)

Benzalkonium chloride (BAK) is a detergent-type preservative that disrupts the lipid layer of the tear film and is directly toxic to corneal epithelial cells with chronic exposure.

Question 84: When cleaning the objective lens of a slit lamp biomicroscope, the correct technique is to:

Use a lens-cleaning solution with a lint-free cloth, wiping gently from center outward (Correct answer)
Use a dry cotton swab in a vigorous circular motion to remove debris
Rinse with tap water and pat dry with a soft cloth
Apply 70% isopropyl alcohol directly to the glass surface with a paper towel

Correct answer: Use a lens-cleaning solution with a lint-free cloth, wiping gently from center outward

Optical surfaces should be cleaned using an appropriate lens-cleaning solution and a lint-free cloth, wiping from center outward to avoid dragging debris across the optical surface. Isopropyl alcohol can damage coatings, and dry or abrasive materials can scratch the lens.

Question 85: An EOG is performed with a measured dark trough of 360 µV and a light peak of 414 µV, yielding an Arden ratio of approximately 1.15. The simultaneous full-field ERG is entirely normal. Which conclusion is MOST appropriate?

The result is normal — an Arden ratio above 1.0 indicates intact RPE function
The abnormal EOG with normal ERG is the classic dissociation pattern of Best disease (vitelliform macular dystrophy) (Correct answer)
The result suggests diffuse RPE atrophy from advanced age-related macular degeneration
An abnormal EOG is only diagnostically significant when accompanied by an abnormal ERG

Correct answer: The abnormal EOG with normal ERG is the classic dissociation pattern of Best disease (vitelliform macular dystrophy)

The Arden ratio = Light Peak ÷ Dark Trough = 414 ÷ 360 ≈ 1.15 (115%). A normal Arden ratio is ≥1.85 (185%), so this result is markedly abnormal. The EOG measures RPE function through the standing electrical potential driven by ion channels (bestrophin chloride channels) in the RPE. The hallmark of Best disease (caused by BEST1/VMD2 mutations in bestrophin) is a severely reduced Arden ratio with a characteristically NORMAL full-field ERG — this EOG–ERG dissociation is pathognomonic. Option C is explicitly incorrect because Best disease is diagnosed precisely by this dissociation. Diffuse RPE atrophy from AMD would typically also show ERG changes and a different clinical context.

Question 86: When calibrating a fundus camera for standardized disc photography in a patient with high myopia (–10.00 D), the photographer must apply a correction factor to accurate linear measurements because:

High minus lenses in the indirect condensing system shift the nodal point, invalidating the Littmann correction formula assumptions (Correct answer)
Myopic eyes have reduced pupil responsiveness, causing uneven illumination artifacts in disc images
The camera's internal optics introduce barrel distortion proportional to refractive error
High myopia elongates the axial length, making the actual disc appear larger on the retina than the image magnification suggests

Correct answer: High minus lenses in the indirect condensing system shift the nodal point, invalidating the Littmann correction formula assumptions

The Littmann formula for correcting fundus camera magnification assumes a standard nodal point position. In high myopia, the elongated globe shifts the position of the eye's second nodal point posteriorly, and when strong minus auxiliary lenses are introduced into the optical path, the effective magnification changes in a way that the standard formula does not fully account for. The correction factor must incorporate the patient's refractive error (the 'ametropia correction') to yield accurate disc measurements.

Question 87: During visual acuity testing, a 5-year-old correctly identifies 4 out of 5 optotypes on the 20/32 line but fails on the 20/25 line. How should this result be recorded?

20/25 +4
20/25
20/32 (Correct answer)
20/32 -1

Correct answer: 20/32

Visual acuity is recorded as the last line on which the patient correctly identifies the majority of optotypes (at least 3 out of 5 or 4 out of 5 depending on chart type). Since the child correctly identified 4/5 on 20/32 but failed 20/25, the recorded acuity is 20/32. The '-1' notation is optional but the base line is 20/32.

Question 88: Which of the following medications is an alpha-1 adrenergic antagonist used to dilate the pupil without causing cycloplegia?

Tropicamide
Phenylephrine (Correct answer)
Cyclopentolate
Atropine

Correct answer: Phenylephrine

Phenylephrine stimulates alpha-1 receptors in the dilator pupillae muscle causing mydriasis without affecting the ciliary muscle, so accommodation is preserved.

Question 89: A photograph of the optic disc shows a cup-to-disc ratio of 0.8. This finding is most clinically significant when combined with:

Superior or inferior neuroretinal rim thinning (Correct answer)
A positive history of cataracts
Hyperopic refraction
Myopia greater than −1.00 D

Correct answer: Superior or inferior neuroretinal rim thinning

A large C/D ratio alone is not diagnostic; superior or inferior rim thinning (ISNT rule violation) increases suspicion for glaucomatous damage.

Question 90: Which federal law specifically prohibits ophthalmic practices from referring patients to outside facilities in which the referring physician has a financial interest, unless a specific exception applies?

OSHA Bloodborne Pathogen Standard
HIPAA
The Stark Law (Physician Self-Referral Law) (Correct answer)
The False Claims Act

Correct answer: The Stark Law (Physician Self-Referral Law)

The Stark Law (42 U.S.C. § 1395nn) prohibits physicians from referring Medicare and Medicaid patients to entities providing designated health services in which the physician or an immediate family member has a financial relationship, unless a statutory exception applies. HIPAA addresses privacy, the False Claims Act addresses billing fraud, and OSHA governs workplace safety.

Question 91: What is the purpose of a typoscope in a low vision rehabilitation program?

To measure intraocular pressure in low vision patients
To project a magnified image of text onto a monitor screen
To isolate a single line of text, reducing surrounding glare and improving contrast for reading (Correct answer)
To formally test a patient's contrast sensitivity function

Correct answer: To isolate a single line of text, reducing surrounding glare and improving contrast for reading

A typoscope is a black card with a slot that frames one line of text at a time, blocking surrounding white page glare and enhancing contrast to improve reading performance.

Question 92: Which of the following is an example of a closed-ended question during patient history taking?

'Do you have diabetes?' (Correct answer)
'What makes your symptoms worse?'
'How has your vision changed recently?'
'Can you describe your vision problem?'

Correct answer: 'Do you have diabetes?'

Closed-ended questions require a yes/no or specific answer, such as confirming the presence of a medical condition.

Question 93: A patient complains of eyestrain and distorted vision with new progressive addition lenses, despite having worn progressives before. The FIRST verification step should be to:

Replace the lenses with flat-top bifocals
Reduce the near addition power by 0.25 D
Add antireflective coating to reduce glare
Verify the optical center height and monocular PD against the patient's measurements (Correct answer)

Correct answer: Verify the optical center height and monocular PD against the patient's measurements

Complaints of distortion and eyestrain with progressive lenses most commonly result from incorrect fitting parameters, particularly the optical center height or monocular PD being off. The first step is always to verify that the lenses were made to the correct measurements before considering prescription changes or alternative lens designs.

Question 94: During dark adaptation, the Purkinje shift refers to which phenomenon?

The transition from L-cone dominance to M-cone dominance during twilight vision
The lateral migration of cone photopigments toward the foveal center under low-light conditions
A shift in peak spectral sensitivity from ~555 nm (photopic) to ~507 nm (scotopic) as illumination decreases (Correct answer)
A paradoxical increase in visual acuity near the optic disc during scotopic adaptation

Correct answer: A shift in peak spectral sensitivity from ~555 nm (photopic) to ~507 nm (scotopic) as illumination decreases

The Purkinje shift describes the change in the eye's peak spectral sensitivity from approximately 555 nm (green-yellow, cone-mediated photopic vision) to approximately 507 nm (blue-green, rod-mediated scotopic vision) as luminance decreases. This is why red objects appear relatively brighter in daylight but blue objects appear relatively brighter at dusk — rods are more sensitive to shorter wavelengths than cones.

Question 95: The macula lutea gets its yellow color from which pigments?

Hemoglobin and transferrin
Lutein and zeaxanthin (Correct answer)
Xanthophyll and beta-carotene
Melanin and rhodopsin

Correct answer: Lutein and zeaxanthin

Lutein and zeaxanthin are carotenoid pigments concentrated in the macula that filter blue light and protect against oxidative damage.

Question 96: After instilling 0.1% pilocarpine in both eyes of a patient with a large, poorly reactive right pupil (suspected Adie's tonic pupil), the right pupil constricts briskly to 3 mm while the left shows no significant response. This differential response is diagnostic because:

0.1% pilocarpine is a standard threshold dose that constricts all pupils regardless of innervation status
Healthy iris sphincters require 1% pilocarpine for constriction; Adie's pupils paradoxically resist all cholinergic agents
Postganglionic parasympathetic denervation of the ciliary ganglion causes iris sphincter supersensitivity, allowing response to concentrations too dilute to affect normally innervated muscle (Correct answer)
The aberrant cholinergic fibers in Adie's pupil amplify the pilocarpine signal through ciliary ganglion hyperexcitability

Correct answer: Postganglionic parasympathetic denervation of the ciliary ganglion causes iris sphincter supersensitivity, allowing response to concentrations too dilute to affect normally innervated muscle

In Adie's tonic pupil, postganglionic parasympathetic denervation of the ciliary ganglion causes denervation supersensitivity of the iris sphincter muscle, with upregulation of muscarinic receptors. The supersensitive sphincter constricts in response to 0.1% pilocarpine, a concentration far too weak to affect a normally innervated sphincter (which requires approximately 1% pilocarpine for a reliable response). This differential response — robust constriction in the Adie's pupil, no response in the normal fellow eye — confirms the diagnosis. Full-strength 1% pilocarpine would constrict both pupils and has no diagnostic value for Adie's.

Question 97: When obtaining a patient's ocular history, asking about prior LASIK or refractive surgery is important primarily because it affects:

IOP measurements and IOL power calculations (Correct answer)
Tear film evaluation
Pupil dilation response
Color vision testing results

Correct answer: IOP measurements and IOL power calculations

Prior corneal refractive surgery alters corneal curvature and thickness, making standard IOP measurements and IOL power calculations inaccurate without correction factors.

Question 98: Using the Titmus stereofly test, a patient correctly identifies the fly as three-dimensional but fails all nine animal targets and all circles. A second patient fails to perceive the fly in 3D but correctly identifies 3 of the 9 animals. Which conclusion is best supported?

Patient 2 has better stereoacuity than Patient 1 because the animal targets require finer disparity detection than the fly (Correct answer)
Both patients have equivalent stereoacuity deficits since both fail portions of the test
Patient 1's fly perception indicates normal stereopsis; the animal and circle failures are likely monocular cue responses
Patient 1 has better stereoacuity than Patient 2 because perceiving the fly requires coarser stereopsis

Correct answer: Patient 2 has better stereoacuity than Patient 1 because the animal targets require finer disparity detection than the fly

The Titmus stereofly is a gross stereopsis target detectable at approximately 3000 arcseconds of disparity — it is the coarsest target on the test and can be perceived through monocular cues (the wings create a vivid 3D percept even monocularly in some patients). The nine animal targets require ~400–100 arcseconds, and the Wirt circles range from 800 to 40 arcseconds. Patient 1's isolated fly response with failure of all finer targets strongly suggests a monocular cue response rather than true stereopsis. Patient 2, who detects some animal targets, demonstrates finer true binocular disparity detection despite failing the fly.

Question 99: A patient is asked to follow a penlight in the six cardinal positions of gaze. In left gaze, the right eye shows limited adduction and the left eye shows nystagmoid movements. Which cranial nerve or structure is most likely affected?

Right CN VI
Right medial longitudinal fasciculus (MLF) (Correct answer)
Left CN III
Left CN VI

Correct answer: Right medial longitudinal fasciculus (MLF)

Internuclear ophthalmoplegia (INO) is caused by a lesion in the medial longitudinal fasciculus (MLF). A right MLF lesion impairs adduction of the right eye in left gaze, while the contralateral (left) eye shows abducting nystagmus. The MLF connects the CN VI nucleus to the contralateral CN III nucleus.

Question 100: Which imaging modality is considered the gold standard for diagnosing choroidal neovascularization (CNV) location and activity in wet AMD?

Fluorescein angiography (Correct answer)
Fundus autofluorescence
B-scan ultrasonography
Infrared reflectance imaging

Correct answer: Fluorescein angiography

Fluorescein angiography remains the gold standard for characterizing CNV type (classic vs. occult), boundaries, and activity to guide anti-VEGF treatment decisions.

Question 101: A patient's employer calls the ophthalmic practice requesting the results of a recent visual acuity exam, stating it is needed to determine whether the patient can continue working as a truck driver. How should the COT handle this request?

Transfer the call to the ophthalmologist who can release information verbally
Decline to release any information without a signed patient authorization or court order (Correct answer)
Release only the visual acuity result since it is not a diagnosis
Provide the information because occupational safety is a HIPAA exception

Correct answer: Decline to release any information without a signed patient authorization or court order

Under HIPAA, a patient's employer is not automatically authorized to receive protected health information. Even occupational relevance does not override this requirement. A signed patient authorization or a legally valid court order or subpoena is required before any PHI can be released to an employer.

Question 102: When performing retinoscopy at 50 cm, what is the working distance lens value that must be subtracted?

+2.00 D (Correct answer)
+1.50 D
+2.50 D
+1.00 D

Correct answer: +2.00 D

At 50 cm, vergence = 1/0.50 = +2.00 D, so +2.00 D must be subtracted from the gross finding to obtain the net refraction.

Question 103: Which contact lens parameter describes the curvature of the back surface of the lens?

Center thickness
Optical zone
Diameter
Base curve radius (Correct answer)

Correct answer: Base curve radius

The base curve radius (BCR) describes the curvature of the posterior (back) surface of a contact lens.

Question 104: A COT whose certification expired 14 months ago wants to reinstate their credential. According to JCAHPO policy, which reinstatement pathway applies?

Reinstatement by retaking and passing the full COT examination (Correct answer)
Reinstatement by continuing education units alone, with no examination required
Reinstatement is impossible after 12 months; the technician must begin with COA certification
Reinstatement via a provisional reinstatement status lasting 6 months

Correct answer: Reinstatement by retaking and passing the full COT examination

JCAHPO allows reinstatement of a lapsed COT credential within a defined window, but once the lapse exceeds one year the credential cannot be reinstated through CEUs alone — the individual must retake and pass the full COT certification examination to regain the credential. There is no provisional status or mandatory demotion to COA.

Question 105: A patient with a lesion at the level of the lateral geniculate nucleus (LGN) would most likely present with which visual field defect?

Monocular scotoma
Congruous homonymous hemianopia
Bitemporal hemianopia
Incongruous homonymous hemianopia (Correct answer)

Correct answer: Incongruous homonymous hemianopia

Lesions at the lateral geniculate nucleus tend to produce incongruous homonymous hemianopias because fibers from corresponding retinal points in each eye have not yet fully reorganized into the precise retinotopic mapping that develops more posteriorly in the visual pathway. Bitemporal hemianopia occurs at the chiasm; congruous defects are more characteristic of occipital cortex lesions; monocular scotomas occur anterior to the chiasm.

Question 106: Which communication technique is most appropriate when explaining a new diagnosis to an anxious patient?

Use complex medical terminology to appear authoritative
Use plain language, maintain eye contact, and allow questions (Correct answer)
Speak quickly to reduce their anxiety sooner
Avoid the topic to prevent further distress

Correct answer: Use plain language, maintain eye contact, and allow questions

Plain language, eye contact, and open dialogue promote patient understanding and build trust in anxious patients.

Question 107: A 34-year-old patient is being evaluated for contact lens fitting. Corneal topography reveals a best-fit sphere of 43.50 D centrally, significant inferior steepening of 2.80 D, and an I-S value of 3.1 D on the KISA% index calculation. Pachymetry shows a minimum thickness of 468 µm at a point displaced inferiorly. What is the MOST appropriate clinical conclusion?

Pellucid marginal degeneration requiring large-diameter gas-permeable lens fitting
Normal corneal topography variant suitable for standard soft toric contact lens fitting
Contact lens-induced corneal warpage — discontinue lens wear for 4–6 weeks and repeat topography
Subclinical or early keratoconus — contact lens fitting should proceed only after informing the patient of progression risk (Correct answer)

Correct answer: Subclinical or early keratoconus — contact lens fitting should proceed only after informing the patient of progression risk

An I-S value >1.4 D, inferior steepening >1.5 D relative to the superior cornea, and minimum pachymetry <500 µm at an inferiorly displaced thinnest point are all diagnostic indicators of subclinical or forme fruste keratoconus. The KISA% index values above 60% are suspicious and above 100% are diagnostic. While contact lenses may still be fitted, the patient must be counseled about keratoconus progression risk, the need for serial topographic monitoring, and the contraindication to LASIK. Pellucid marginal degeneration shows inferior thinning with steepening above the thinning zone, a different topographic pattern.

Question 108: Which optical device can be mounted on spectacles to redirect images from a blind visual field area into the patient's seeing field?

Fresnel prism (Correct answer)
Reading stand magnifier
High-plus reading lens
CCTV camera

Correct answer: Fresnel prism

Fresnel prisms attached to spectacle lenses shift images from the hemianopic or sector-loss field into the functional seeing field, providing field expansion.

Question 109: A high-index lens material with n=1.74 will be thinner than a standard CR-39 lens (n=1.50) because:

It absorbs more UV light
It is lighter in weight
Higher index requires less curvature to achieve the same power (Correct answer)
It has better impact resistance

Correct answer: Higher index requires less curvature to achieve the same power

Higher index materials bend light more efficiently, allowing flatter (less curved) surfaces that produce thinner lenses for the same prescription.

Question 110: When refining cylinder axis with the Jackson cross cylinder, the patient reports that flip position 1 and flip position 2 look equally blurry. This means:

The axis must be rotated toward the plus dot
The cylinder power is too low
The axis is correctly positioned (Correct answer)
The axis must be rotated toward the minus dot

Correct answer: The axis is correctly positioned

Equal blur in both JCC positions means the cylinder axis is correctly placed at the midpoint between the two flip orientations.

Question 111: In fluorescein angiography, 'window defect' hyperfluorescence is caused by:

Leakage from new vessels
Staining of fibrous tissue
Pooling in a pigment epithelial detachment
Loss of RPE blocking pigment revealing background choroidal fluorescence (Correct answer)

Correct answer: Loss of RPE blocking pigment revealing background choroidal fluorescence

Window defects occur when RPE atrophy or thinning removes the normal blocking layer, allowing background choroidal fluorescence to shine through.

Question 112: During a scleral buckle procedure for a complex retinal detachment, the surgeon has placed a circumferential band and now requests cryotherapy. The technician notices the cryoprobe tip has formed an ice ball that is NOT releasing from the scleral surface. What is the most appropriate immediate action?

Switch the cryo unit to defrost mode and flush the tip with warm saline
Apply gentle traction to detach the probe before the freeze cycle ends
Irrigate the tip with cold BSS to accelerate the thaw
Wait for passive thawing of the ice ball before attempting to remove the probe (Correct answer)

Correct answer: Wait for passive thawing of the ice ball before attempting to remove the probe

If a cryoprobe ice ball adheres to the sclera, the correct action is passive thawing — waiting until the ice ball melts naturally before attempting removal. Applying traction can tear the sclera or underlying choroid. Cold BSS will not thaw the ice and may worsen adhesion. Defrost mode exists on some units, but the safest universal protocol is passive thaw, avoiding any mechanical force.

Question 113: A patient with a nanophthalmic eye has an axial length of 18.8 mm and steep keratometry of 48.50 D. Using the Hoffer Q formula, the IOL power calculated is +32.0 D. The surgeon is also given a calculation using the SRK/T formula yielding +29.5 D. Which of the following best explains the difference and guides proper formula selection for this case?

SRK/T is more accurate for short eyes because it uses a regression-derived A-constant that was specifically validated on nanophthalmic axial lengths below 20 mm
The two formulas differ because SRK/T applies a keratometry correction factor for steep corneas above 46 D that lowers the IOL power recommendation, while Hoffer Q does not
The Hoffer Q formula was specifically designed and validated for short eyes (AL < 22 mm) and uses a personalized ACD (pACD) prediction that better estimates effective lens position in small eyes; SRK/T systematically underestimates IOL power in short eyes due to its regression origin (Correct answer)
Hoffer Q overestimates IOL power in all eyes below 22 mm due to a mathematical artifact in the ELP prediction; the SRK/T result should be used because it produces less hyperopic outcomes in nanophthalmic patients

Correct answer: The Hoffer Q formula was specifically designed and validated for short eyes (AL < 22 mm) and uses a personalized ACD (pACD) prediction that better estimates effective lens position in small eyes; SRK/T systematically underestimates IOL power in short eyes due to its regression origin

The Hoffer Q formula was derived and validated specifically for short axial lengths (particularly AL < 22.0 mm) and has consistently been shown to produce the most accurate outcomes in this subgroup. Its ELP prediction variable — the personalized ACD (pACD) — scales more appropriately for the compressed anterior segment geometry of small eyes. SRK/T, while excellent for average to long eyes, was developed as a theoretical formula primarily validated on normal-range eyes; it tends to underestimate the required IOL power in very short eyes, leading to hyperopic outcomes. For nanophthalmic eyes, Hoffer Q (or newer generation formulas like Holladay 2 or Barrett Universal II with biometric data) is preferred. The ~2.5 D discrepancy between formulas is expected and clinically significant in this range.

Question 114: A student with a reading disability is taking a state science assessment. Which of the following would be considered a supplemental testing accommodation rather than a modification?

Having questions read aloud to the student (Correct answer)
Reducing the number of test questions by 50%
Allowing the student to answer orally instead of in writing
Removing all time limits from the assessment

Correct answer: Having questions read aloud to the student

Having questions read aloud is a testing accommodation — it changes how the student accesses the test content without altering what is being measured. Reducing questions or removing time limits may cross into modifications that change the construct being assessed, while oral responses change the response format fundamentally.

Question 115: Carbonic anhydrase inhibitors, such as dorzolamide, lower intraocular pressure by what mechanism of action?

Blocking beta-adrenergic receptors in the ciliary body
Constricting the pupil to open the trabecular meshwork
Reducing aqueous humor production (Correct answer)
Increasing uveoscleral outflow

Correct answer: Reducing aqueous humor production

Carbonic anhydrase inhibitors (CAIs) work by suppressing the carbonic anhydrase enzyme in the ciliary body. This action reduces the formation of bicarbonate ions, which in turn decreases the production of aqueous humor and lowers intraocular pressure.

Question 116: Phacoemulsification makes use of which type of waves?

Ultrasound waves (Correct answer)
Infrared waves
Ultraviolet waves
Radio waves

Correct answer: Ultrasound waves

Ultrasound waves are used in phacoemulsification to break the nucleus into smaller fragments for easy removal via a small corneal incision.

Question 117: A patient claims vision of 20/400 in the right eye following a workplace injury. Without informing the patient, the examiner positions the Snellen chart at 10 feet instead of the standard 20 feet. The patient reads the line labeled '20/100' with effort. What is this patient's calculated actual visual acuity for this eye?

20/400
20/100
20/50 (Correct answer)
20/200

Correct answer: 20/50

When the standard chart is viewed at half the normal distance (10 feet instead of 20 feet), every optotype subtends twice its standard angular size at the eye. To calculate actual acuity: (testing distance ÷ standard distance) × denominator of line read = (10 ÷ 20) × 100 = 50. The patient's actual acuity is therefore 20/50 — far better than the claimed 20/400. This half-distance Snellen technique is a validated method for detecting functional (non-organic) vision loss when the patient's claimed acuity is inconsistent with their behavior or other objective findings.

Question 118: A 47-year-old commercial pilot has 20/15 BCVA bilaterally, normal dilated fundus exam, normal Humphrey visual fields, and normal brightness acuity tester (BAT) results. He reports significant difficulty reading low-contrast cockpit instruments under reduced ambient lighting. Pelli-Robson contrast sensitivity testing yields 1.05 log units (normal ≥1.65 log units). Which etiology is LEAST consistent with this isolated contrast sensitivity deficit?

Fully corrected myopia with current spectacle prescription (Correct answer)
Early diabetic maculopathy not yet visible ophthalmoscopically
Age-related lens changes producing increased intraocular light scatter
Subclinical optic neuritis from early multiple sclerosis

Correct answer: Fully corrected myopia with current spectacle prescription

Fully corrected myopia does not impair contrast sensitivity. Uncorrected myopia degrades retinal image quality and reduces CS, but once the refractive error is properly corrected with spectacles or contact lenses, the optical blur is resolved and CS returns to the neurally normal baseline. In contrast, subclinical optic neuritis (demyelination slows signal conduction and impairs spatial frequency processing), early diabetic maculopathy (photoreceptor and RPE changes precede visible funduscopic signs), and lens scatter (intraocular forward scatter degrades retinal contrast even with 20/20 Snellen acuity) are all established causes of isolated CS loss with preserved Snellen acuity.

Question 119: A patient presents with right hypotropia following blunt orbital trauma. Forced duction testing demonstrates resistance to passive elevation of the right eye. Active force generation testing of the right superior rectus shows near-normal force. Which interpretation is most accurate?

Left superior rectus overaction producing a relative hypotropia in the right eye
Skew deviation secondary to posterior fossa involvement
Mechanical restriction of the right inferior rectus consistent with orbital floor entrapment (Correct answer)
Right superior rectus paresis — the weakened muscle is unable to elevate the eye actively

Correct answer: Mechanical restriction of the right inferior rectus consistent with orbital floor entrapment

Forced duction testing assesses passive movement. Resistance to elevation indicates a mechanical tether preventing the eye from moving upward — most consistent with inferior rectus entrapment in an orbital floor fracture. The near-normal active force generation of the superior rectus confirms the muscle itself is intact and functional; it simply cannot overcome the restriction. If the superior rectus were paretic, forced duction would be unrestricted (the eye would move passively without resistance), and active force generation would be reduced.

Question 120: When performing keratometry on a patient with dry eye, the technician observes mires breaking up quickly. The BEST approach is to:

Record the reading from the broken mires as an average
Instill artificial tears, wait briefly, then reattempt measurement (Correct answer)
Dilate the patient before keratometry
Increase the keratometer's illumination to compensate

Correct answer: Instill artificial tears, wait briefly, then reattempt measurement

A dry, irregular tear film disrupts the reflected mires; lubricating drops temporarily stabilize the tear film for a more accurate reading.

Question 121: A school's COT coordinator is reviewing whether a student qualifies for oral administration of a written exam as a supplemental testing format. Which condition would MOST appropriately support this accommodation?

The student is a non-native English speaker who finds reading in English slow
The student prefers verbal expression over written responses
The student has a documented print disability such as dyslexia that significantly impairs reading decoding (Correct answer)
The student's classroom teacher reports the student performs better verbally than in writing

Correct answer: The student has a documented print disability such as dyslexia that significantly impairs reading decoding

Oral administration as a supplemental format is appropriate for students with documented print disabilities (e.g., dyslexia) that impair their ability to access print-based test items. Language background and personal preference do not constitute qualifying conditions. Teacher observation alone, without a formal evaluation, is insufficient to authorize this accommodation.

Question 122: When recording keratometry results, 43.50 D @ 180° / 45.00 D @ 90° represents a cornea with:

1.50 D of against-the-rule astigmatism
No astigmatism because both values are normal
1.50 D of with-the-rule astigmatism (Correct answer)
1.50 D of oblique astigmatism

Correct answer: 1.50 D of with-the-rule astigmatism

With-the-rule astigmatism means the steeper meridian is near 90°; here 45.00 D @ 90° is steeper, giving 1.50 D WTR astigmatism.

Question 123: Which of the following describes an A-pattern esotropia?

Esotropia only in upgaze
Greater esotropia in downgaze compared to upgaze
Greater esotropia in upgaze compared to downgaze (Correct answer)
Equal esotropia in all positions of gaze

Correct answer: Greater esotropia in upgaze compared to downgaze

An A-pattern esotropia has greater convergence (esotropia) in upgaze and less or exotropia in downgaze.

Question 124: The duction test measures:

Binocular alignment
Monocular range of movement (Correct answer)
Fusional vergence amplitudes
Stereoacuity at near

Correct answer: Monocular range of movement

Duction testing assesses the monocular range of eye movement with the fellow eye occluded.

Question 125: A technician performing automated perimetry notices a patient's reliability indices show 28% fixation losses, 0% false positives, and 0% false negatives on a 24-2 SITA Standard field. How should this result be interpreted?

The field is unreliable due to high fixation losses and should be repeated after retraining the patient (Correct answer)
Fixation losses above 20% always indicate poor fixation, making the field uninterpretable
The field is reliable because false positives and false negatives are both 0%
The SITA algorithm corrects for fixation losses, so the result is valid regardless of this index

Correct answer: The field is unreliable due to high fixation losses and should be repeated after retraining the patient

Fixation losses >20% indicate the patient is not maintaining steady fixation on the central target, as the Heijl-Krakau method detected responses during blind spot presentations. While 0% false positives and negatives suggest the patient understood the task and wasn't trigger-happy or missing stimuli deliberately, the high fixation loss rate compromises spatial reliability — scotomas may appear shifted or artifacts introduced. Repeating after patient retraining is standard protocol. SITA does not internally correct for fixation errors.

Question 126: The Specular microscope measures which property of the corneal endothelium?

Anterior chamber depth
Corneal curvature and astigmatism
Endothelial cell density and morphology (Correct answer)
Corneal pachymetry only

Correct answer: Endothelial cell density and morphology

Specular microscopy analyzes the reflected image of the endothelial cell mosaic to measure cell density (cells/mm²), cell size variation (CV), and hexagonality.

Question 127: The cobalt blue filter on a slit lamp is used in conjunction with fluorescein dye primarily to evaluate:

Corneal epithelial defects (Correct answer)
Optic nerve cupping
Vitreous opacities
Lens clarity

Correct answer: Corneal epithelial defects

Cobalt blue light excites sodium fluorescein, which pools in corneal epithelial defects and fluoresces green, revealing the defect's extent.

Question 128: Microcystic corneal edema seen at the slit lamp is an early sign of which contact lens problem?

Mechanical trauma from lens edge
Chronic corneal hypoxia from insufficient oxygen transmissibility (Correct answer)
Giant papillary conjunctivitis
Allergic reaction to lens solution

Correct answer: Chronic corneal hypoxia from insufficient oxygen transmissibility

Microcystic edema (epithelial microcysts) develops when chronic hypoxia disrupts normal epithelial cell metabolism and turnover.

Question 129: In wide-field retinal imaging (e.g., Optos), the peripheral retina is captured using which optical principle?

Ellipsoidal mirror scanning (Correct answer)
Slit-lamp biomicroscopy
Confocal aperture imaging
Direct ophthalmoscopy

Correct answer: Ellipsoidal mirror scanning

Wide-field systems like Optos use an ellipsoidal mirror to redirect the scanning laser beam across up to 200° of the retina.

Question 130: A patient is diagnosed with left superior oblique palsy. During double Maddox rod testing, one rod is placed before each eye with the cylinder axes oriented vertically (producing horizontal streaks). Which torsional finding is most expected in the left eye?

Bilateral excyclotorsion greater than 10° in each eye
Excyclotorsion of the right eye only, with no measurable torsion in the left eye
Excyclotorsion (extorsion) of the left eye, because the superior oblique is the primary intortor (Correct answer)
Incyclotorsion (intorsion) of the left eye, because the superior oblique normally extorts

Correct answer: Excyclotorsion (extorsion) of the left eye, because the superior oblique is the primary intortor

The superior oblique is the primary intortor of the eye. With left SO palsy, its intorsion function is lost, and the unopposed inferior oblique (an extortor and elevator) causes the left eye to excyclotort. On double Maddox rod testing, the horizontal streak seen by the left eye appears tilted relative to the right eye's streak — the angular difference between the two streaks quantifies the degree of excyclotorsion. Bilateral excyclotorsion >10° per eye raises suspicion for bilateral SO palsy.

Question 131: A JCAHPO-certified ophthalmic technician who is convicted of a felony may face:

No action unless the crime is work-related
Automatic upgrade to COMT
A mandatory 10-hour ethics course only
Suspension or revocation of certification (Correct answer)

Correct answer: Suspension or revocation of certification

Felony convictions can result in suspension or revocation of JCAHPO certification under its disciplinary procedures.

Question 132: Which stimulus size is the standard default for automated static perimetry on the Humphrey Field Analyzer?

Goldmann V
Goldmann II
Goldmann I
Goldmann III (Correct answer)

Correct answer: Goldmann III

Goldmann Size III (0.43° diameter) is the standard stimulus used for automated threshold perimetry on the Humphrey Field Analyzer.

Question 133: A patient with keratoconus would most likely be best corrected with which type of contact lens?

Bandage soft lens
Daily disposable soft lens
Extended-wear silicone hydrogel
Rigid gas-permeable lens (Correct answer)

Correct answer: Rigid gas-permeable lens

Rigid gas-permeable lenses mask the irregular corneal surface of keratoconus by creating a smooth refractive interface with the tear lens.

Question 134: What does a 'plus carrier' lenticular design in a rigid contact lens provide?

Extra minus power in the periphery to reduce spherical aberration
A thicker peripheral zone to improve lid interaction and superior positioning (Correct answer)
Increased optical zone size for large pupils
Additional plus power to correct presbyopia

Correct answer: A thicker peripheral zone to improve lid interaction and superior positioning

A plus carrier lenticular edge is thicker at the periphery, encouraging the upper lid to ride over and center the lens in a lid-attachment fit.

Question 135: In a vitreoretinal surgical suite, the assistant is setting up for a pars plana vitrectomy (PPV) with planned silicone oil tamponade. The surgeon specifies 5000 centistoke (cs) silicone oil. Compared to 1000 cs silicone oil, which statement about 5000 cs oil is TRUE and directly affects assistant preparation?

5000 cs oil must be warmed to 37°C before injection to achieve adequate flow through standard cannulas
5000 cs oil emulsifies more rapidly than 1000 cs oil, shortening the expected time to removal
5000 cs oil requires a dedicated, higher-pressure injector system because of its greater viscosity, and the assistant must confirm the correct injector is loaded before the tamponade step (Correct answer)
5000 cs oil is less buoyant than 1000 cs oil and provides inferior inferior retinal tamponade

Correct answer: 5000 cs oil requires a dedicated, higher-pressure injector system because of its greater viscosity, and the assistant must confirm the correct injector is loaded before the tamponade step

Silicone oil viscosity directly affects injection mechanics. 5000 cs oil is significantly more viscous than 1000 cs and cannot be injected through standard tubing at typical pressures—it requires a dedicated high-pressure/high-torque injector (e.g., a viscous fluid injector). If the assistant loads the wrong injector, the oil cannot be delivered or the system may fail catastrophically. Both 1000 cs and 5000 cs oils have similar buoyancy (both are lighter than vitreous); 5000 cs actually emulsifies less rapidly; and routine warming is not a standard protocol step.

Question 136: The axons of which retinal ganglion cell subtype project preferentially to the koniocellular layers of the lateral geniculate nucleus and are thought to carry short-wavelength (blue-yellow) color opponent signals?

Parasol (M-type) ganglion cells
Midget (P-type) ganglion cells
Bistratified ganglion cells (Correct answer)
Intrinsically photosensitive retinal ganglion cells (ipRGCs)

Correct answer: Bistratified ganglion cells

Small bistratified retinal ganglion cells receive ON input from short-wavelength (S-cone) bipolar cells in their inner dendritic tier and OFF input from medium/long-wavelength (M/L-cone) bipolar cells in their outer tier, creating a blue-ON/yellow-OFF chromatic opponent signal. These cells project to the koniocellular (K) layers interleaved between the magnocellular and parvocellular layers of the LGN, distinct from the M-pathway (parasol cells → magnocellular LGN) and P-pathway (midget cells → parvocellular LGN).

Question 137: What does the term 'oxygen transmissibility' (Dk/t) measure in contact lenses?

Oxygen passing through a lens of specific thickness (Correct answer)
Ion permeability of the lens material
Lens surface wettability
Rate of lens dehydration

Correct answer: Oxygen passing through a lens of specific thickness

Dk/t (transmissibility) is calculated by dividing the oxygen permeability (Dk) by the lens center thickness (t).

Question 138: A rigid gas-permeable (RGP) contact lens that is fit too steeply compared to the cornea will show which fluorescein pattern?

Apical clearance (bull's-eye pattern) (Correct answer)
Alignment pattern with uniform green ring
No fluorescein pooling anywhere
Apical touch with peripheral pooling

Correct answer: Apical clearance (bull's-eye pattern)

A steep-fitting RGP shows central fluorescein pooling (apical clearance) with peripheral edge seal, creating a bull's-eye appearance.

Question 139: During a Parks three-step test, a patient has a right hypertropia that increases in left gaze and increases with right head tilt. Which muscle is most likely paretic?

Right superior oblique (Correct answer)
Left inferior rectus
Right inferior oblique
Left superior rectus

Correct answer: Right superior oblique

The Parks three-step test isolates a single cyclovertical muscle. Step 1: right hypertropia → paretic muscle is a right depressor or left elevator. Step 2: increases in left gaze → right superior oblique or right inferior rectus. Step 3: increases with right head tilt → right superior oblique (which would normally intort in right head tilt). All three steps converge on the right superior oblique as the paretic muscle.

Question 140: When scrubbing in for ophthalmic surgery, the technician should perform a surgical hand scrub for a minimum of how many minutes according to standard protocol?

1 minute if wearing two pairs of sterile gloves
10 minutes using plain soap
3 to 5 minutes using an antiseptic agent (Correct answer)
30 seconds with alcohol-based handrub only

Correct answer: 3 to 5 minutes using an antiseptic agent

Standard surgical scrub protocol requires 3–5 minutes with an antiseptic solution (e.g., chlorhexidine or povidone-iodine) to reduce resident and transient skin flora.

Question 141: A COT is assessing a 7-year-old child referred for difficulty copying from the board. Which near vision acuity test is MOST appropriate for this patient?

HOTV chart at 14 inches
Tumbling E chart at 20 feet
Reduced Snellen chart at 14 inches (Correct answer)
Jaeger chart at 14 inches

Correct answer: Reduced Snellen chart at 14 inches

The reduced Snellen chart at 14 inches is the standard near acuity test for school-age children who know their letters. It measures near visual acuity at the typical reading distance. The Jaeger chart uses print sizes rather than standardized Snellen notation. HOTV and Tumbling E are used for preschool children who cannot identify letters. Tumbling E at 20 feet tests distance, not near acuity.

Question 142: When calibrating a Goldmann-compatible fundus camera for stereoscopic disc photography using the simultaneous stereoscopic method, the technician notices that the two half-images have unequal magnification on review. Which of the following is the MOST likely cause?

The flash synchronization is offset between the two film planes causing sequential rather than simultaneous capture
The patient's pupil is less than 5 mm, causing asymmetric vignetting of the two optical paths
The beam splitter prism is laterally decentered relative to the camera's optical axis (Correct answer)
The camera's diopter compensation dial is set incorrectly for the patient's refractive error

Correct answer: The beam splitter prism is laterally decentered relative to the camera's optical axis

In simultaneous stereoscopic fundus photography, the beam splitter divides the exit pupil into two half-apertures that image the fundus from slightly different angles onto two separate film planes or sensor areas. If the prism is laterally decentered from the optical axis, one light path subtends a larger effective aperture angle than the other, producing different magnification (and potentially different distortion) in each half-image. A small pupil causes symmetric vignetting of both paths equally. Diopter compensation affects focus but not relative magnification between the two channels. Flash sync issues would cause blur in one image, not magnification difference.

Question 143: Which condition is most likely to cause a falsely HIGH axial length on A-scan?

Small pupil during measurement
High myopia with corneal irregularity
Posterior staphyloma with probe misalignment (Correct answer)
Dense nuclear sclerosis

Correct answer: Posterior staphyloma with probe misalignment

Posterior staphyloma creates an abnormal retinal contour; if the probe misses the fovea, it records a longer path length.

Question 144: A patient with a dense nuclear sclerotic cataract undergoes potential acuity meter (PAM) testing and scores 20/40. Postoperative visual acuity following cataract extraction is only 20/80. Which finding MOST likely explains this discrepancy?

The PAM overestimated acuity because the laser beam bypassed a central scotoma caused by undetected macular pathology (Correct answer)
PAM results are inherently unreliable in eyes with posterior subcapsular cataracts
The PAM underestimated acuity because the cataract scattered the projected beam excessively
The patient did not fixate properly during PAM testing, invalidating the result

Correct answer: The PAM overestimated acuity because the laser beam bypassed a central scotoma caused by undetected macular pathology

The PAM projects a Snellen chart through a narrow beam that bypasses lens opacities, potentially missing a central scotoma from macular disease. If a scotoma is present but the beam happens to land on intact retina adjacent to the fovea, the PAM can falsely predict better acuity than the patient will actually achieve post-surgery. This is a recognized limitation — PAM does not assess the full macular field and can overestimate potential in cases of subtle macular degeneration, epiretinal membrane, or other central retinal pathology.

Question 145: What does the Mean Deviation (MD) value on a Humphrey Field Analyzer report represent?

The number of depressed points on the Total Deviation plot
The difference between the best and worst threshold values
The average sensitivity across all test points compared to age-matched normals (Correct answer)
The standard deviation of threshold values within the field

Correct answer: The average sensitivity across all test points compared to age-matched normals

Mean Deviation is the average deviation of all measured thresholds from age-corrected normal values, with negative values indicating overall field depression.

Question 146: What is the unit used to measure prismatic effect in spectacle lenses?

Meter angle
Prism diopter (Δ) (Correct answer)
Diopter
Radian

Correct answer: Prism diopter (Δ)

Prismatic effect in ophthalmic optics is measured in prism diopters (Δ), where 1Δ = 1 cm deviation per meter.

Question 147: Corneal scrapings from a patient with a chronic, non-healing ulcer are plated and grow filamentous colonies with chalky-white aerial hyphae that partially dip into the agar after 5–7 days at 35°C. Modified acid-fast staining is weakly positive. Which organism and its MOST appropriate primary treatment are correctly paired?

Fusarium solani — treated with topical natamycin 5%
Nocardia asteroides — treated with topical trimethoprim-sulfamethoxazole or amikacin (Correct answer)
Actinomyces israelii — treated with topical penicillin G drops
Streptomyces species — treated with topical ciprofloxacin 0.3%

Correct answer: Nocardia asteroides — treated with topical trimethoprim-sulfamethoxazole or amikacin

Nocardia asteroides is an aerobic, weakly gram-positive, partially acid-fast actinomycete. Key morphology: thin, branching filaments with aerial hyphae that embed into agar (unlike true fungi). Weak acid-fast positivity (modified Kinyoun stain) is a hallmark. It causes chronic, indolent keratitis, particularly after trauma. Treatment is topical trimethoprim-sulfamethoxazole or amikacin (sometimes combined). Fusarium keratitis is acid-fast negative and not filamentous in the same manner; Actinomyces is anaerobic and not acid-fast; Streptomyces would not be weakly acid-fast positive and is rarely a clinical corneal pathogen.

Question 148: The foveal avascular zone (FAZ) receives its oxygen supply primarily through which mechanism?

Diffusion from the underlying choriocapillaris (Correct answer)
Anastomotic connections from the cilioretinal artery
Terminal branches of the central retinal artery
Direct perfusion from the deep capillary plexus

Correct answer: Diffusion from the underlying choriocapillaris

The FAZ is devoid of retinal capillaries by definition. The foveal photoreceptors — the most metabolically demanding cells in the retina — rely entirely on diffusion of oxygen and nutrients from the choriocapillaris across Bruch's membrane and the retinal pigment epithelium. This is why macular degeneration, which disrupts the choriocapillaris, is so devastating to central vision.

Question 149: A low vision patient with hemianopic visual field loss following a right occipital stroke is being fitted with a sector prism (Fresnel press-on prism). For a right homonymous hemianopia, where should the prism be positioned on the spectacle lens, and in which direction should the base be oriented?

Base-left (base toward the nose on the right lens) prism on the right half of both lenses to expand awareness into the right hemianopic field
Base-right prism on the right half of both lenses, apex pointing toward the blind field (Correct answer)
Base-in prism on the left half of both lenses to shift images toward the intact field
Base-out prism on the right lens only, covering the full lens surface

Correct answer: Base-right prism on the right half of both lenses, apex pointing toward the blind field

For right homonymous hemianopia, the blind field is to the right. Sector prisms are placed on the side of the blind field (right half of each lens). The base is oriented toward the right (the blind side), which displaces the image of objects in the right blind field toward the intact left visual field, alerting the patient to stimuli in the hemianopic region. Base-in on the left half would not address the right field loss. Full-lens coverage creates disabling diplopia.

Question 150: A retrobulbar block is a type of local anesthesia used for intraocular surgery. Where is the anesthetic agent injected to achieve this block?

Into the space between the sclera and Tenon's capsule (sub-Tenon's).
Into the cone-shaped area behind the globe, containing the optic nerve and extraocular muscles. (Correct answer)
Under the skin of the eyelid (subcutaneous).
Directly into the vitreous cavity.

Correct answer: Into the cone-shaped area behind the globe, containing the optic nerve and extraocular muscles.

A retrobulbar injection places anesthetic into the retrobulbar space, which is the muscle cone located behind the eye (globe). This effectively blocks sensory and motor nerves to the eye, providing profound anesthesia and akinesia (lack of movement) for surgery.

Question 151: A patient with a 3-year history of hydroxychloroquine (Plaquenil) use undergoes multifocal ERG (mfERG). The technician notes a parafoveal ring of significantly reduced response amplitude, while the central foveal response appears relatively preserved. Which interpretation is most accurate?

This parafoveal ring scotoma is a characteristic early finding of hydroxychloroquine retinal toxicity (Correct answer)
This pattern indicates artifactual suppression from poor central fixation during the recording
Reduced parafoveal amplitude with relative foveal sparing is a normal variant in patients over age 50
Preserved foveal response with reduced parafoveal response indicates optic nerve dysfunction, not retinal pathology

Correct answer: This parafoveal ring scotoma is a characteristic early finding of hydroxychloroquine retinal toxicity

Hydroxychloroquine toxicity produces a characteristic parafoveal ring of photoreceptor damage that appears topographically on mfERG as reduced amplitude in a ring pattern surrounding the fovea. The fovea may be relatively spared early in toxicity — this 'bull's-eye' distribution is diagnostically significant and differs from the concentric foveal suppression seen with poor fixation or the diffuse amplitude reduction seen with optic nerve disease.

Question 152: In Duane retraction syndrome type I, which movement is primarily limited?

Adduction
Depression in adduction
Abduction (Correct answer)
Elevation in adduction

Correct answer: Abduction

Duane type I is characterized by limited or absent abduction due to misfiring of the lateral rectus by the oculomotor nerve.

Question 153: Corneal neovascularization (pannus) associated with contact lens wear is primarily caused by:

Chronic hypoxia stimulating new blood vessel growth into the cornea (Correct answer)
Mechanical trauma from lens edge lift
Allergic reaction to lens care solution preservatives
Excessive lens movement abrading the limbal area

Correct answer: Chronic hypoxia stimulating new blood vessel growth into the cornea

Prolonged corneal hypoxia triggers angiogenic factors (VEGF) that stimulate limbal blood vessel growth into the normally avascular cornea.

Question 154: During potential acuity meter (PAM) testing on a patient with a 3+ nuclear sclerotic cataract, the technician obtains a PAM reading of 20/200. Preoperative corneal topography shows no significant irregularity. Which interpretation is MOST accurate?

PAM readings are artificially reduced by dense nuclear sclerosis, making this result likely an underestimate of true potential acuity (Correct answer)
A PAM reading of 20/200 with a grade 3+ cataract confirms the cataract alone accounts for the reduced vision
The result indicates the patient has amblyopia, making cataract surgery unlikely to improve vision
The PAM result is reliable and indicates poor postoperative prognosis due to underlying macular pathology

Correct answer: PAM readings are artificially reduced by dense nuclear sclerosis, making this result likely an underestimate of true potential acuity

Dense nuclear sclerotic cataracts significantly degrade the quality of the laser beam used in PAM testing, causing artifactually low readings that underestimate true macular potential. A grade 3+ nuclear sclerosis can prevent adequate transmission of the PAM stimulus. Therefore, the 20/200 result likely underestimates postoperative potential, and additional testing (e.g., ultrasound B-scan, laser interferometry) should be considered before concluding there is macular pathology.

Question 155: Which action by the ophthalmic technician is appropriate when the surgeon calls for 'more viscoelastic' during IOL implantation?

Add the OVD directly to the irrigation bottle
Aspirate residual OVD first to make room before adding more
Load a fresh viscoelastic cannula and hand it handle-first to the surgeon (Correct answer)
Inject BSS through the side-port to supplement the OVD

Correct answer: Load a fresh viscoelastic cannula and hand it handle-first to the surgeon

A pre-loaded cannula handed handle-first maintains the sterile transfer technique and allows the surgeon to inject immediately without repositioning.

Question 156: During a glaucoma drainage device (tube shunt) implantation, the surgeon ligates the tube with a 7-0 polyglactin (Vicryl) suture to prevent early hypotony. The assistant is asked to create a 'ripcord.' What material is used and what is its function?

A 3-0 or 4-0 nylon suture is passed through the tube lumen alongside the ligature; when pulled post-operatively at the slit lamp, it breaks the Vicryl and opens the tube to aqueous flow (Correct answer)
A 7-0 nylon suture is threaded through the tube and secured to the conjunctiva so the surgeon can reopen the tube intraoperatively if pressure spikes
A 10-0 nylon suture is used to externally reinforce the Vicryl ligature and is left exposed for laser suture lysis at 4–6 weeks
A 5-0 polypropylene suture is tied around the tube exterior and the free end is buried in Tenon's capsule to dissolve over time

Correct answer: A 3-0 or 4-0 nylon suture is passed through the tube lumen alongside the ligature; when pulled post-operatively at the slit lamp, it breaks the Vicryl and opens the tube to aqueous flow

A ripcord technique involves threading a 3-0 or 4-0 nylon suture through the lumen of the tube before or after placing the Vicryl ligature. The suture's free end is left accessible (typically tucked under conjunctiva with the end accessible at the limbus). Once the Vicryl has served its purpose (preventing early hypotony in the first few weeks), the clinician can pull the nylon suture at the slit lamp, mechanically tearing the Vicryl and allowing aqueous to flow through the device. This is preferred over waiting for Vicryl absorption. Options B, C, and D misidentify the mechanism—laser suture lysis and external sutures do not pass through the tube lumen.

Question 157: A COT is assisting with a low vision evaluation for a patient with bilateral advanced glaucoma exhibiting an inferior arcuate scotoma in the right eye and a superior nasal step in the left. The patient struggles most with reading the bottom half of printed lines. Which prism strategy is theoretically most appropriate for reading rehabilitation?

Yoked prism with base-down OD and base-up OS to create monocular field expansion
Base-up prism OU to shift the retinal image superiorly onto intact superior retina
Base-in prism OU to reduce convergence demand and relax accommodation during near tasks
Base-down prism OU to shift printed text upward in the visual field, away from the inferior scotoma (Correct answer)

Correct answer: Base-down prism OU to shift printed text upward in the visual field, away from the inferior scotoma

An inferior arcuate scotoma affects the superior visual field (by the retinal inversion principle). The patient cannot see objects appearing in the upper portion of their visual field with the right eye — which corresponds to reading the top of a printed page. However, the question states the patient struggles with the BOTTOM half of lines, suggesting the scotoma or functional loss affects the inferior visual field (corresponding to a superior retinal defect, or the superior nasal step of the left eye causing inferior field loss). Base-down prism displaces the visual field image upward, shifting text that appears at the bottom of the field into the intact inferior visual field region. This is an advanced clinical concept requiring careful correlation between field defect location, retinal coordinates, and prism effect direction.

Question 158: JCAHPO was formally established in which decade?

1970s (Correct answer)
1960s
1990s
1950s

Correct answer: 1970s

JCAHPO was formally established in the 1970s to develop credentialing standards for ophthalmic allied health personnel.

Question 159: A patient enrolled in an IRB-approved ophthalmic research study signs informed consent at enrollment. Six months into the study, the patient develops moderate dementia and can no longer meaningfully understand the study procedures or risks. The patient's adult daughter presents herself as the decision-maker and requests that her parent remain enrolled. What is the most ethically appropriate course of action?

Pause participation, consult the IRB, and follow the study protocol's provisions for surrogate consent before making any decision (Correct answer)
Continue participation since valid informed consent was obtained at the time of enrollment and was legally sufficient
Allow the daughter to provide surrogate consent verbally and proceed without further delay
Withdraw the patient from the study immediately without any possibility of continued participation

Correct answer: Pause participation, consult the IRB, and follow the study protocol's provisions for surrogate consent before making any decision

Research ethics require ongoing decisional capacity — consent obtained at enrollment does not carry forward indefinitely when a participant loses capacity. Federal regulations (45 CFR 46) and Good Clinical Practice guidelines require that the IRB-approved protocol specify how loss of capacity is handled. The IRB must be consulted, and surrogate consent (if permitted by the protocol and applicable law) must follow a formal process. Simply continuing based on prior consent or informal surrogate agreement is ethically and legally insufficient.

Question 160: A biologic indicator using Geobacillus stearothermophilus spores shows GROWTH after a completed autoclave sterilization cycle. The run log shows the chamber reached 121°C. Which explanation is MOST likely responsible for the sterilization failure?

G. stearothermophilus is intrinsically resistant to moist heat and should not be used for steam sterilization validation
The exposure time exceeded the standard protocol, inducing heat-shock protein expression and spore survival
Residual air in the chamber prevented steam penetration, creating a cool pocket that never reached lethal temperature (Correct answer)
The autoclave exceeded 134°C briefly, paradoxically reactivating thermophilic spores

Correct answer: Residual air in the chamber prevented steam penetration, creating a cool pocket that never reached lethal temperature

G. stearothermophilus is the standard biologic indicator for gravity-displacement and pre-vacuum autoclaves because its spores are highly heat-resistant but reliably destroyed at 121°C with adequate steam contact. If growth occurs despite a logged 121°C reading, the most common cause is incomplete air evacuation — trapped air creates insulating pockets that prevent steam from contacting the load at the lethal combination of temperature, moisture, and time. The thermocouple measures chamber air temperature, not load temperature inside an air pocket.

Question 161: Which test is used to evaluate the relative afferent pupillary defect (RAPD)?

Swinging flashlight test (Correct answer)
Worth 4-dot test
Cover test
Hirschberg test

Correct answer: Swinging flashlight test

The swinging flashlight test compares the direct and consensual pupillary light responses in each eye and detects RAPD when the pupil dilates as the light swings to the affected eye.

Question 162: During automated perimetry using the SITA Standard algorithm on a 24-2 test pattern, a patient demonstrates a mean deviation (MD) of -8.5 dB with a pattern standard deviation (PSD) of 9.2 dB. The glaucoma hemifield test (GHT) reads 'Outside Normal Limits.' Which interpretation is MOST consistent with these indices?

Diffuse loss consistent with early cataracts or media opacity
Unreliable field due to high false-positive rate
Generalized depression only, no focal damage present
Localized arcuate scotoma pattern consistent with glaucomatous damage (Correct answer)

Correct answer: Localized arcuate scotoma pattern consistent with glaucomatous damage

A high PSD (9.2 dB) in the context of moderate MD (-8.5 dB) indicates that the loss is NOT uniform — there is significant variability across test points, suggesting localized defects superimposed on some generalized loss. An arcuate scotoma pattern (localized nerve fiber bundle loss) produces exactly this pattern. Diffuse media opacity causes a high MD depression but LOW PSD (uniformly reduced). An unreliable field would be flagged by catch trial indices, not these threshold values. The GHT being 'Outside Normal Limits' confirms asymmetric superior/inferior hemifield differences consistent with glaucoma.

Question 163: An A-scan is performed on a patient whose eye was previously filled with 1000-centistoke silicone oil following a complex retinal detachment repair. The technician uses the default phakic velocity setting of 1548 m/s. Compared to the true axial length, the displayed measurement will be:

Falsely shorter, because silicone oil has higher acoustic impedance than vitreous, causing the sound wave to travel faster and return earlier
Falsely longer, because the ultrasound velocity through silicone oil (~980 m/s) is much slower than the default setting, causing the instrument to calculate a longer distance for the same transit time (Correct answer)
Falsely shorter, because the ultrasound velocity through silicone oil (~980 m/s) is much slower than the default setting, so the instrument calculates a shorter distance for the same transit time
Accurate, because modern A-scan units automatically detect the acoustic impedance mismatch at the vitreo-silicone interface and compensate the velocity calculation

Correct answer: Falsely longer, because the ultrasound velocity through silicone oil (~980 m/s) is much slower than the default setting, causing the instrument to calculate a longer distance for the same transit time

The A-scan instrument calculates distance using: Distance = Velocity × (Transit Time / 2). When silicone oil fills the vitreous cavity, the actual ultrasound velocity through that segment is ~980 m/s (significantly slower than normal vitreous at ~1532 m/s). If the technician uses the default velocity of 1548 m/s, the instrument assumes the sound traveled faster than it actually did, and since the transit time is real (and longer than expected for that distance), the calculated distance comes out falsely long. The technician must either use a dedicated silicone oil velocity setting or apply a mathematical correction. A separate measurement of the cornea-to-posterior lens surface (using phakic velocity for those segments) and then the silicone oil segment alone (at 980 m/s) must be summed.

Question 164: During visual examination of a completed structural steel weld, the inspector measures the weld face and finds the center of the weld crown is 7mm above the base metal plane on a flat position weld with a specified maximum convexity of 3mm. The correct action is to:

Reject the weld for excessive convexity (Correct answer)
Accept the weld since convexity adds strength
Mark it for radiographic testing before deciding
Accept it if the weld legs meet the minimum size requirement

Correct answer: Reject the weld for excessive convexity

Excessive convexity is a rejectable condition because an overly high crown creates a stress concentration at the weld toes and does not meet code-specified dimensional requirements. The weld must be rejected and repaired by grinding to bring the convexity within the allowable limit. Convexity does not add usable strength and actually introduces notch effects.

Question 165: Which parameter does the technician monitor on the phacoemulsification machine to prevent thermal wound burns during cataract surgery?

Intraocular pressure readout only
Footpedal position sensor feedback
Microscope illumination intensity
Irrigation flow rate and aspiration vacuum (Correct answer)

Correct answer: Irrigation flow rate and aspiration vacuum

Adequate irrigation flow must always exceed aspiration to cool the phaco tip and prevent frictional heat from burning the corneal incision.

Question 166: When calculating the expected spherical equivalent soft contact lens power for a patient whose spectacle Rx is -9.00 DS at a vertex distance of 14 mm, what is the correctly vertex-adjusted contact lens power?

-9.00 D
-7.75 D
-8.00 D
-8.25 D (Correct answer)

Correct answer: -8.25 D

Vertex distance compensation is required for powers ≥±4.00 D. Using the formula F_cl = F_spec / (1 − d × F_spec), where d = 0.014 m: F_cl = −9.00 / (1 − 0.014 × (−9.00)) = −9.00 / 1.126 ≈ −7.99 D, which rounds to −8.00 D clinically. However, the nearest available soft lens power is −8.25 D in most fitting sets, making −8.25 D the correct dispensed choice to avoid undercorrection.

Question 167: A patient with nystagmus is scheduled for fundus photography. Which technique best compensates for uncontrolled eye movement?

Switch to red-free filter
Use a shorter flash duration (Correct answer)
Dilate the pupil more widely
Increase flash intensity

Correct answer: Use a shorter flash duration

A shorter flash duration (high-speed flash) freezes eye movement and reduces motion blur in patients with nystagmus.

Question 168: Which type of collagen is the predominant component of the vitreous humor?

Type II collagen (Correct answer)
Type IV collagen
Elastin fibers
Type I collagen

Correct answer: Type II collagen

Type II collagen fibrils form the scaffolding of the vitreous gel, interspersed with hyaluronic acid.

Question 169: During a cataract extraction procedure, the surgeon needs to create a continuous circular opening in the anterior lens capsule. Which of the following instruments would the surgeon most likely request for this specific step, known as capsulorhexis?

Utrata forceps (Correct answer)
Sinskey hook
Bishop-Harmon forceps
Westcott scissors

Correct answer: Utrata forceps

Utrata forceps, also known as capsulorhexis forceps, are specifically designed with fine, grasping tips to grip and tear the anterior lens capsule in a controlled, circular manner to perform a capsulorhexis. A cystotome, a type of bent needle, can also be used for this step.

Question 170: A lens with a cylinder power of -1.50 at axis 90 is equivalent in cross-cylinder notation to which combination?

Plano combined with +1.50 at axis 90
+1.50 sphere combined with -1.50 at axis 180
-1.50 sphere combined with +1.50 at axis 90
Plano combined with -1.50 at axis 90 (Correct answer)

Correct answer: Plano combined with -1.50 at axis 90

A pure cylinder lens has plano power in one meridian and cylinder power in the perpendicular meridian.

Question 171: Which class of ophthalmic drugs works by primarily decreasing the production of aqueous humor to lower intraocular pressure?

Prostaglandin analogs
Miotics
Mydriatics
Beta-blockers (Correct answer)

Correct answer: Beta-blockers

Beta-blockers, such as timolol, are a first-line treatment for glaucoma and function by blocking beta receptors in the ciliary body, which reduces the production of aqueous humor, thereby lowering intraocular pressure.

Question 172: When documenting a patient's chief complaint, which element is MOST important to record first?

Current medications
Onset, location, duration, character, and associated symptoms (Correct answer)
Duration of symptoms
Family history of eye disease

Correct answer: Onset, location, duration, character, and associated symptoms

A thorough chief complaint includes onset, location, duration, character, associated symptoms, relieving/aggravating factors, and prior treatments (OLDCART framework).

Question 173: A technician is preparing a patient for cataract surgery. The patient has signed the consent form, but while reviewing the procedure, they state, "I'm a little nervous because I don't really understand what the doctor is going to do with the new lens." What is the technician's most appropriate response?

Pause all preparations and inform the surgeon that the patient has further questions and may not fully understand the procedure. (Correct answer)
Provide the patient with a brochure about cataract surgery to read while they wait.
Proceed with the pre-operative preparations as consent has already been signed.
Reassure the patient that the surgeon is very experienced and they shouldn't worry.

Correct answer: Pause all preparations and inform the surgeon that the patient has further questions and may not fully understand the procedure.

Informed consent is a communication process, not just a signature on a form. If a patient expresses a lack of understanding, it indicates that true informed consent has not been achieved. The technician's duty is to stop the process and notify the surgeon, who is ultimately responsible for ensuring the patient fully comprehends the procedure, risks, and benefits before moving forward.

Question 174: Gives the physician an estimate of a patient's potential visual acuity

Buphthalmos
Iris Bombe
Metal Test Spheres
PAM Test (Correct answer)

Correct answer: PAM Test

A test used to estimate a patient's potential visual acuity, often before cataract surgery, by projecting an eye chart image onto the retina.

Question 175: The Amsler grid is primarily used to detect defects in which area of the visual field?

Peripheral visual field beyond 30 degrees
Nasal step defects near the blind spot
Central 20 degrees of vision, particularly the macula (Correct answer)
Superior arcuate region associated with glaucoma

Correct answer: Central 20 degrees of vision, particularly the macula

The Amsler grid tests the central 20 degrees of vision and is most sensitive for detecting metamorphopsia and scotomas caused by macular disease.

Question 176: A patient undergoing automated perimetry consistently presses the response button when no light stimulus is presented. On the Humphrey Field Analyzer printout, this will be recorded as a high number of:

False negatives
False positives (Correct answer)
Pattern deviations
Fixation losses

Correct answer: False positives

False positives occur when a patient responds (presses the button) in the absence of a light stimulus. This indicates that the patient is "trigger happy" and can compromise the reliability of the test results.

Question 177: You are performing retinoscopy on an uncooperative patient and inadvertently work at 40 cm instead of your intended 67 cm. Compared to what you would have found at 67 cm, how does this error affect the gross sphere finding required to neutralize the reflex?

The distance change only affects the brightness of the reflex, not the neutralization power
Neutralization requires more plus (or less minus) power at 40 cm than at 67 cm (Correct answer)
Neutralization requires more minus (or less plus) power at 40 cm than at 67 cm
Neutralization power is identical at both distances; only speed of the reflex differs

Correct answer: Neutralization requires more plus (or less minus) power at 40 cm than at 67 cm

A shorter working distance means the examiner's far point is closer, which acts as a stronger plus lens effectively added to the system. At 67 cm, the working distance lens is 1/0.67 ≈ +1.50 D; at 40 cm it is 1/0.40 = +2.50 D. To neutralize the reflex, you must account for this increased effective plus. Practically, working closer makes every patient appear more myopic (or less hyperopic) to the retinoscope, so you must add more plus (or remove more minus) in your trial lenses to reach the neutral reflex point. After subtracting the actual working distance lens used, the net result should ideally be the same — but errors in working distance directly corrupt the gross finding.

Question 178: Transient viral vesicles that infect the facial area

Herpes Simplex Virus Type 1 (Correct answer)
Herpes Simplex Virus Type 5
Herpes Simplex Virus Type 4
Herpes Simplex Virus Type 2

Correct answer: Herpes Simplex Virus Type 1

This virus commonly causes cold sores or fever blisters on the lips or around the mouth. It can also cause genital herpes.

Question 179: In supplemental testing protocol, a 'nonstandard administration' differs from a 'standard accommodation' primarily in that:

Nonstandard administrations are only available to students with physical disabilities
Nonstandard administrations alter what the test measures, while standard accommodations change only how it is delivered (Correct answer)
Nonstandard administrations require parental consent, while standard accommodations do not
Nonstandard administrations are always administered individually, while standard accommodations can occur in group settings

Correct answer: Nonstandard administrations alter what the test measures, while standard accommodations change only how it is delivered

The core distinction is construct validity: standard accommodations change the delivery format without altering the construct being measured (e.g., extended time for a reading test still measures reading). Nonstandard administrations change the test in ways that may alter what is being measured, which is why scores may require special reporting. Setting and disability type do not define this boundary.

Question 180: The vitreous humor occupies what percentage of the total volume of the eye?

90%
40%
60%
80% (Correct answer)

Correct answer: 80%

The vitreous humor occupies approximately 80% of the total ocular volume, filling the posterior segment between the lens and retina.

Question 181: A microbiology technician is examining a culture that produces a green-blue pigment and has a fruity odor. The organism is gram-negative, non-fermentative, and grows at 42°C. Which organism is most likely responsible?

Acinetobacter baumannii
Klebsiella pneumoniae
Pseudomonas aeruginosa (Correct answer)
Escherichia coli

Correct answer: Pseudomonas aeruginosa

Pseudomonas aeruginosa characteristically produces pyocyanin (blue-green pigment) and has a grape-like or fruity odor due to aminoacetophenone. It is gram-negative, non-fermentative, oxidase-positive, and can grow at 42°C, which distinguishes it from other Pseudomonas species.

Question 182: What is the standard working distance used in retinoscopy, and what lens does the examiner add to neutralize this distance?

67 cm / +1.50 D
50 cm / +2.00 D (Correct answer)
100 cm / +1.00 D
33 cm / +3.00 D

Correct answer: 50 cm / +2.00 D

The standard retinoscopy working distance is 67 cm (adding +1.50 D) or 50 cm (adding +2.00 D); 67 cm/+1.50 D is most common in the US.

Question 183: A basic telescopic system used for distance low vision consists of which optical components?

Two concave lenses aligned in series
A bifocal segment and a plano carrier
An objective lens and an ocular (eyepiece) lens (Correct answer)
A prism pair and a concave mirror

Correct answer: An objective lens and an ocular (eyepiece) lens

A telescope uses an objective (front) lens to collect and focus light and an ocular (eyepiece) lens through which the patient views the resulting magnified image.

Question 184: During retinoscopy at a 50 cm working distance, the examiner neutralizes the reflex using +3.25 –1.50 × 180 in the trial frame. After accounting for the working distance lens, what is the patient's actual refractive error?

+1.25 –1.50 × 180 (Correct answer)
+3.25 –1.50 × 180
+1.25 –1.50 × 090
+5.25 –1.50 × 180

Correct answer: +1.25 –1.50 × 180

At 50 cm, the working distance requires a +2.00 D correction (1/0.50 m = +2.00 D). This is subtracted from the gross sphere finding only: +3.25 – 2.00 = +1.25 D sphere. The cylinder power and axis are properties of the astigmatism and are unchanged by the working distance correction. The net prescription is +1.25 –1.50 × 180.

Question 185: The A-constant in IOL power calculation is specific to:

A particular IOL model and its position in the eye (Correct answer)
The axial length measurement technique
The surgeon's phaco technique
The patient's corneal curvature

Correct answer: A particular IOL model and its position in the eye

The A-constant is lens-specific and accounts for the IOL's design and expected effective lens position.

Question 186: Which one of the following is NOT a technique for nucleus removal in phacoemulsification?

Stop and chop technique
Cut and paste technique (Correct answer)
Chip and flip technique
Direct chop technique
Divide and conquer technique

Correct answer: Cut and paste technique

A scrub technician must be familiar with the names of the different techniques used in Phacoemulsification, as the machine settings are different in each and the operating surgeon often needs help from the scrub technician for changing parameters during surgery. <br>Chip and flip, divide and conquer, stop and chop and direct chop are all techniques used for phacoemulsification.

Question 187: During static retinoscopy, the examiner uses a streak retinoscope. Rotating the streak reveals the principal meridians of astigmatism when the streak is:

Perpendicular to the axis of the reflex
Horizontal only
Aligned parallel to the axis of the reflex to show the fastest or brightest reflex (Correct answer)
At 45° to the reflex

Correct answer: Aligned parallel to the axis of the reflex to show the fastest or brightest reflex

In streak retinoscopy, aligning the streak with a principal meridian shows the reflex in that meridian most clearly for neutralization.

Question 188: A patient scores 11/14 on Ishihara color plates (using the 14-plate screening set). Which of the following is the most precise classification of this result?

Conclusive blue-yellow (tritan) deficiency, requiring Farnsworth D-15 confirmation
Mild red-green deficiency — a score below 13/14 on the screening set indicates deficiency (Correct answer)
Normal color vision — one or two missed plates within the normal threshold
The Ishihara test cannot classify severity; only the Farnsworth-Munsell 100-Hue test can

Correct answer: Mild red-green deficiency — a score below 13/14 on the screening set indicates deficiency

On the standard 14-plate Ishihara screening set, a score of 13 or 14 correct is considered normal. Scoring 12 or below indicates a red-green color deficiency (protan or deutan). At 11/14, this patient clearly falls into the deficient range. Ishihara plates are specifically designed to detect red-green deficiencies and cannot reliably detect blue-yellow (tritan) defects — ruling out answer C. Answer D is incorrect because Ishihara does provide a pass/fail classification even if it doesn't quantify severity as precisely as FM-100.

Question 189: A patient presents with an inability to abduct their left eye (turn it outward). A lesion of which cranial nerve is the most likely cause of this deficit?

Cranial Nerve IV (Trochlear)
Cranial Nerve VI (Abducens) (Correct answer)
Cranial Nerve II (Optic)
Cranial Nerve III (Oculomotor)

Correct answer: Cranial Nerve VI (Abducens)

Cranial nerve VI, the abducens nerve, innervates the lateral rectus muscle, which is solely responsible for abduction (outward movement) of the eye. Therefore, a lesion of CN VI would result in an inability to abduct the eye on the affected side. CN III innervates most of the other extraocular muscles, and CN IV innervates the superior oblique.

Question 190: A COT is performing a visual assessment of a patient's seated posture. The patient exhibits a forward head posture with increased cervical lordosis and rounded shoulders. Which of the following structures is MOST likely to be adaptively shortened?

Scalenes and lower trapezius
Deep cervical flexors and rhomboids
Suboccipital muscles and pectoralis minor (Correct answer)
Cervical extensors and serratus anterior

Correct answer: Suboccipital muscles and pectoralis minor

In classic forward head posture with rounded shoulders, the suboccipital muscles (which extend the upper cervical spine, creating the 'chin poke') and pectoralis minor (which protracts and tilts the scapula anteriorly, contributing to rounded shoulders) are adaptively shortened. The deep cervical flexors and rhomboids are typically lengthened and weak in this posture pattern.

Question 191: A patient's OCT shows a 'double hump' or 'W-shape' reflectivity profile in the outer retina. This pattern is most associated with:

Normal foveal pit anatomy (Correct answer)
Macular hole
Central serous chorioretinopathy
Vitelliform macular dystrophy

Correct answer: Normal foveal pit anatomy

The normal foveal OCT profile shows a central pit flanked by the thicker parafoveal retina, creating a characteristic 'W' or double-hump appearance.

Question 192: Which organization serves as the accrediting body that works alongside JCAHPO to accredit ophthalmic medical personnel training programs?

JCAHO
ACAHPO
ABOM
CoA-OMP (Correct answer)

Correct answer: CoA-OMP

The Commission on Accreditation of Ophthalmic Medical Personnel (CoA-OMP) accredits training programs aligned with JCAHPO standards.

Question 193: A patient is being measured with Goldmann applanation tonometry immediately after a corneal refractive surgery (LASIK) that removed tissue from the central stroma. Compared to the pre-LASIK reading, the post-LASIK GAT measurement will most likely:

Remain accurate because LASIK does not affect applanation physics
Overestimate IOP because the flap creates added resistance
Underestimate IOP due to reduced central corneal thickness and altered corneal biomechanics (Correct answer)
Overestimate IOP due to increased corneal curvature post-ablation

Correct answer: Underestimate IOP due to reduced central corneal thickness and altered corneal biomechanics

LASIK reduces central corneal thickness (CCT) and alters corneal biomechanics, making the cornea easier to applanate. This causes GAT to underestimate true IOP — sometimes by 4–8 mmHg depending on the ablation depth. This is clinically critical because post-LASIK glaucoma suspects may appear to have normal IOP when it is actually elevated. Corneal hysteresis is also reduced post-LASIK, compounding the error.

Question 194: The refractive index assumed by most manual keratometers when converting radius of curvature to diopters is approximately:

1.000
1.336
1.3375 (Correct answer)
1.376

Correct answer: 1.3375

Most manual keratometers use a standardized keratometric refractive index of 1.3375 to convert corneal radius to diopters.

Question 195: When fitting a toric soft lens, the lens consistently rotates 15° counterclockwise (as viewed from the examiner's perspective). To correct for this misrotation, the cylinder axis of the ordered lens should be:

Left unchanged; toric lens rotation is compensated by prism ballast redesign
Rotated 15° clockwise from the spectacle axis
Increased by 15° in absolute axis value regardless of direction
Rotated 15° counterclockwise from the spectacle axis (Correct answer)

Correct answer: Rotated 15° counterclockwise from the spectacle axis

Using the LARS rule (Left Add, Right Subtract): if the lens rotates counterclockwise (Left), you Add the degrees of misrotation to the spectacle cylinder axis. For example, if spectacle axis is 180° and the lens rotates 15° counterclockwise, the ordered axis becomes 180° + 15° = 195° (or equivalently 015°). This compensatory shift ensures the cylinder axis aligns correctly on the eye.

Question 196: A patient reports bothersome prismatic color fringing (rainbow halos) around objects when viewing through the periphery of newly dispensed high-index lenses. Which alternative lens material would MOST effectively reduce this chromatic aberration?

High-index 1.67 (Abbe value ≈ 32)
High-index 1.74 (Abbe value ≈ 33)
Trivex (Abbe value ≈ 45) (Correct answer)
Polycarbonate (Abbe value ≈ 30)

Correct answer: Trivex (Abbe value ≈ 45)

Chromatic aberration is inversely proportional to Abbe value: a higher Abbe number means less dispersion of white light into its spectral components and therefore less color fringing. Trivex, with an Abbe value of approximately 45, produces substantially less chromatic aberration than polycarbonate (~30), high-index 1.67 (~32), or high-index 1.74 (~33). The trade-off is that Trivex has a lower refractive index (1.53) than high-index materials, so lenses will be thicker — a meaningful consideration in higher prescriptions.

Question 197: Which instrument performs an objective, automated refraction by measuring wavefront aberrations or Purkinje images?

Autorefractor (Correct answer)
Lensometer
Keratometer
Pachymeter

Correct answer: Autorefractor

An autorefractor objectively measures the refractive error by analyzing reflections from the retina or measuring wavefront errors without patient response.

Question 198: During a busy clinic day, a COT performs a Humphrey visual field test and notices the fixation loss rate is 38% and the false-positive rate is 22%, rendering the test statistically unreliable. The schedule is overbooked and the physician asks the technician to 'just use it — we'll note it was unreliable.' From a medicolegal standpoint, the greatest risk of proceeding without repeating the test is:

That an unreliable field may mask true glaucomatous progression, leading to a failure-to-diagnose claim if the patient later suffers preventable vision loss (Correct answer)
OSHA liability for using defective equipment without logging the malfunction
That the insurance carrier will deny the claim on technical grounds, creating a billing compliance issue
HIPAA violation due to inadequate documentation standards

Correct answer: That an unreliable field may mask true glaucomatous progression, leading to a failure-to-diagnose claim if the patient later suffers preventable vision loss

While billing denial (option C) is a real secondary risk, the primary medicolegal danger is clinical: a visual field with high fixation loss and false positives cannot reliably distinguish true defects from artifact. If glaucoma progresses undetected because management decisions were based on an invalid field, the practice faces potential liability for negligent monitoring. The standard of care requires that unreliable perimetry be repeated or explicitly addressed in clinical decision-making. Documenting 'unreliable' without repeating places the physician in a weak position if a missed progression is later litigated. HIPAA (option A) and OSHA (option D) are not implicated by test-quality issues.

Question 199: When documenting visual acuity 'cc' versus 'sc', these abbreviations refer to:

Cycloplegic versus non-cycloplegic refraction
Near vision versus distance vision
With correction versus without correction (Correct answer)
Right eye versus left eye

Correct answer: With correction versus without correction

'cc' (cum correctione) means with correction; 'sc' (sine correctione) means without correction.

Question 200: A contact lens wearer presents with severe pain disproportionate to clinical findings, a ring-shaped stromal infiltrate, and a history of swimming in a lake while wearing soft lenses. PCR confirms Acanthamoeba keratitis. Which property of Acanthamoeba cysts makes this infection particularly resistant to standard disinfection protocols?

The cyst wall is composed of cellulose and protein, rendering it impermeable to most quaternary ammonium compounds and hydrogen peroxide at standard concentrations (Correct answer)
Cysts undergo metabolic dormancy that requires a 37°C activation temperature before any disinfectant achieves meaningful penetration
Acanthamoeba encysts in biofilm layers on lens cases, where oxygen-deprived conditions neutralize oxidative agents
The organism expresses efflux pumps homologous to those in gram-negative bacteria, actively exporting disinfectants

Correct answer: The cyst wall is composed of cellulose and protein, rendering it impermeable to most quaternary ammonium compounds and hydrogen peroxide at standard concentrations

Acanthamoeba cysts have a double-layered wall composed of cellulose (outer ectocyst) and protein (inner endocyst), which makes them highly resistant to quaternary ammonium compounds (found in older multipurpose solutions) and even to hydrogen peroxide systems at standard 3% concentration with short contact times. This structural impermeability — not efflux pumps or metabolic dormancy — is the key resistance mechanism, which is why prolonged biguanide (PHMB) or polyhexamethylene biguanide therapy is required for treatment.

Question 201: When performing corneal topography, the Placido disc system measures corneal curvature by analyzing:

Reflected concentric ring images from the corneal surface (Correct answer)
Interference fringes from the tear film
Scattered light from the stroma
Purkinje reflections from the lens

Correct answer: Reflected concentric ring images from the corneal surface

Placido-based topographers project concentric rings onto the cornea and calculate curvature from the spacing and shape of their reflections.

COT - Certified Ophthalmic Technician Exam

The JCAHPO COT exam certifies ophthalmic technicians, assessing competency in clinical ophthalmic skills including patient care, diagnostic testing, surgical assisting, and ophthalmic imaging.

200

Questions

180 min

Time Limit

72%

To Pass

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds