ABO NOCE Basic Opticianry Exam — Questions and Answers

Question 1: A patient wears OD +4.00 D and OS plano. The OD is decentered 4 mm outward. How much horizontal prism imbalance exists between the two eyes?

1.60Δ (Correct answer)
0Δ
4.00Δ
0.80Δ

Correct answer: 1.60Δ

OD: Δ = 4.00 × 0.4 = 1.60Δ; plano OS produces 0Δ regardless of decentration; total imbalance = 1.60Δ.

Question 2: Which unit for distance (d) must be used in Prentice's Rule formula Δ = P × d?

Millimeters
Centimeters (Correct answer)
Prism diopters
Meters

Correct answer: Centimeters

Prentice's Rule requires distance in centimeters; using millimeters without converting gives an answer 10 times too large.

Question 3: The aberration that causes a lens to focus an image onto a curved surface rather than a flat plane is known as:

Curvature of Field (Correct answer)
Longitudinal Chromatic Aberration
Pincushion Distortion
Oblique Astigmatism

Correct answer: Curvature of Field

Curvature of field, or Petzval curvature, describes the tendency of a simple lens to form an image on a curved surface. This can cause the periphery of an image to be out of focus when the center is in focus, or vice-versa.

Question 4: When using a lensometer (lensmeter) to neutralize a lens, the mires are brought into sharp focus. For a spherocylindrical lens, in what order are the power meridians found?

The cylinder is read first when the mires are rotated to 90°
The first clear focus gives the sphere power; the second clear focus gives the sphere + cylinder power (Correct answer)
Both meridians focus simultaneously at the sphere power
The first clear focus gives the cylinder power; the second gives the sphere

Correct answer: The first clear focus gives the sphere power; the second clear focus gives the sphere + cylinder power

In a spherocylindrical lens, focusing the lensometer drum to the first clear set of lines gives the power in one principal meridian (sphere); rotating 90° and refocusing gives the combined power (sphere + cylinder).

Question 5: A 'slab-off' grind on a lens is used to correct which problem in anisometropic patients?

Unequal UV absorption between the two lenses
Difference in cosmetic thickness between lenses
Vertical prismatic imbalance at the reading level (Correct answer)
Chromatic aberration differences between lenses

Correct answer: Vertical prismatic imbalance at the reading level

Slab-off (bicentric grinding) compensates for vertical prismatic imbalance that occurs when anisometropic patients look down to read.

Question 6: When neutralizing a lens with the lensometer, the power rings are brought to sharpest focus and the lines appear broken. This indicates the presence of:

Sphere only
Prism
Base curve error
Cylinder (Correct answer)

Correct answer: Cylinder

Broken or discontinuous lines in the lensometer eyepiece indicate the presence of cylinder (astigmatism) in the lens.

Question 7: In an optical finishing lab where chemicals such as dyes and neutralizers are used, an employee accidentally splashes a solution towards their face. Per Occupational Safety and Health Administration (OSHA) regulations, what specific equipment must be immediately available to the employee?

An eyewash station. (Correct answer)
A standard first-aid kit with bandages.
A fire extinguisher.
A phone to call emergency services.

Correct answer: An eyewash station.

OSHA regulation 29 CFR 1910.151(c) requires that where a person's eyes or body may be exposed to injurious corrosive materials, suitable facilities for quick drenching or flushing of the eyes and body must be provided within the work area for immediate emergency use. An eyewash station is the appropriate and required equipment for this type of incident.

Question 8: When verifying lenses with a lensometer, the cylinder power of a –2.00 –1.50 × 090 lens is measured by:

Reading only when all target lines are clear simultaneously
Setting the drum to –3.50 and reading prism
Noting the difference between the two drum readings when each set of lines clears (Correct answer)
Measuring the sphere and doubling it

Correct answer: Noting the difference between the two drum readings when each set of lines clears

Cylinder power equals the algebraic difference between the two drum readings (first meridian minus second meridian) when each set of lines sharpens.

Question 9: When a patient reports that their new single vision glasses cause objects to appear tilted or slanted, the most likely cause is:

Incorrect sphere power
Cylinder axis error (Correct answer)
Wrong pupillary distance
Excessive base curve

Correct answer: Cylinder axis error

Cylinder axis errors cause objects to appear tilted or slanted because the corrective meridian does not align with the patient's astigmatic axis.

Question 10: Which type of lens treatment darkens when exposed to ultraviolet (UV) radiation and returns to clear when indoors?

Photochromic (Correct answer)
Anti-reflective
Mirror-coated
Polarized

Correct answer: Photochromic

Photochromic lenses contain photochromic molecules that change shape when activated by UV light, causing the lens to darken, and revert to clear when UV exposure is removed.

Question 11: A patient requests a frame with a very small B measurement. Which lens type will be most problematic to fit in this frame?

Flat-top 28 bifocal
Plano sunwear
Progressive addition lens (Correct answer)
Single vision distance

Correct answer: Progressive addition lens

Progressive addition lenses require adequate B measurement (vertical height) to accommodate the full progressive corridor from distance to near.

Question 12: A patient complains that the bottom edge of their new glasses is touching their cheeks, especially when they smile. Which of the following adjustments is the most effective first step to resolve this issue?

Widen the distance between nose pads.
Decrease the pantoscopic tilt. (Correct answer)
Increase the face form wrap.
Lengthen the temples behind the ear.

Correct answer: Decrease the pantoscopic tilt.

Decreasing the pantoscopic tilt (making the frame front more vertical) will move the bottom edge of the frame away from the patient's cheeks. Increasing face form, widening nose pads, or lengthening temples will not effectively address this specific problem.

Question 13: Which patient scenario would experience the MOST noticeable spherical aberration?

Low hyperope (+1.00 D) with average pupil size
Low myope (-1.00 D) with a small pupil in bright light
High hyperope (+6.00 D) with a large pupil in dim light (Correct answer)
Emmetrope wearing plano sunglasses

Correct answer: High hyperope (+6.00 D) with a large pupil in dim light

Spherical aberration increases with both lens power and pupil size, so a high plus prescription combined with a large pupil produces maximum spherical aberration.

Question 14: A patient requires a photochromic lens. Which factor does NOT significantly affect the darkening speed of photochromic lenses?

UV intensity
Temperature
Patient's prescription power (Correct answer)
Lens material

Correct answer: Patient's prescription power

The prescription power of the lens does not significantly affect photochromic darkening speed; temperature, UV intensity, and lens material all do.

Question 15: Which of the following instruments is specifically designed to measure the distance from the posterior surface of a spectacle lens to the apex of the cornea?

Distometer (Correct answer)
Caliper
Lens Clock
Pupilometer

Correct answer: Distometer

A distometer, also known as a vertexometer, is the specialized tool used to measure vertex distance. A pupilometer measures the distance between pupils, a lens clock measures surface curvature, and a caliper measures thickness or diameter.

Question 16: The aqueous humor is a clear fluid that fills the anterior and posterior chambers of the eye. What is its primary drainage pathway out of the eye?

Via the uveoscleral outflow pathway
Through the trabecular meshwork into Schlemm's canal (Correct answer)
Direct absorption by the corneal endothelium
Through the vitreous humor to the optic nerve

Correct answer: Through the trabecular meshwork into Schlemm's canal

The primary, or conventional, pathway for aqueous humor drainage involves the fluid flowing from the anterior chamber through the trabecular meshwork. From there, it enters Schlemm's canal and then drains into the episcleral venous system to return to the general circulation. This pathway regulates intraocular pressure.

Question 17: What does 'sagitta' (sag) describe in ophthalmic lens geometry?

The lens diameter
The optical center location
The depth of a curved surface measured from its chord (Correct answer)
The edge thickness of the lens

Correct answer: The depth of a curved surface measured from its chord

Sagitta is the perpendicular distance from the midpoint of a chord to the curved surface, used to calculate lens thickness.

Question 18: Snell's Law states that n1 sin θ1 = n2 sin θ2. If light travels from air (n=1.00) into glass (n=1.50) at an angle of incidence of 30°, what is the angle of refraction?

30.00°
45.00°
19.47° (Correct answer)
48.59°

Correct answer: 19.47°

1.00 × sin(30°) = 1.50 × sin(θ2). sin(θ2) = 0.5/1.5 = 0.333. θ2 = arcsin(0.333) ≈ 19.47°.

Question 19: Trivex lens material was developed primarily to offer which combination of properties?

Higher refractive index than polycarbonate
High impact resistance with higher Abbe value than polycarbonate (Correct answer)
Greater scratch resistance than glass
Photochromic properties built into the material

Correct answer: High impact resistance with higher Abbe value than polycarbonate

Trivex (PPG Industries) was designed to match polycarbonate's impact resistance while providing a higher Abbe value (~45) for better optical quality.

Question 20: A keratometer (ophthalmometer) is used to measure:

Intraocular pressure
The curvature of the anterior corneal surface (Correct answer)
The refractive power of the entire eye
The thickness of the crystalline lens

Correct answer: The curvature of the anterior corneal surface

The keratometer measures the radius of curvature of the anterior corneal surface, typically used for contact lens fitting.

Question 21: The uvea consists of which three structures?

Optic nerve, retina, and vitreous
Iris, ciliary body, and choroid (Correct answer)
Sclera, episclera, and conjunctiva
Cornea, lens, and retina

Correct answer: Iris, ciliary body, and choroid

The uveal tract is the vascular middle layer of the eye comprising the iris anteriorly, the ciliary body, and the choroid posteriorly.

Question 22: What are the two contemporary formats for writing prescriptions?

Spherical and aspherical
Plus-cylinder and minus-cylinder (Correct answer)
Cross-cylinder and plus-cylinder
Base curve and cross curve

Correct answer: Plus-cylinder and minus-cylinder

Ophthalmic prescriptions for astigmatism can be written in two primary formats: plus-cylinder and minus-cylinder. These formats represent the same optical correction but use different conventions for specifying the cylinder power and axis. Minus-cylinder is more commonly used by optometrists and ophthalmologists, while plus-cylinder is sometimes used in manufacturing or older prescriptions, but both are valid and convertible.

Question 23: A patient complains of a 'swim' sensation after receiving new progressive lenses. The most likely cause is:

Incorrect PD
Excessive pantoscopic tilt
All of the above (Correct answer)
Improper fitting height

Correct answer: All of the above

Swim sensation in progressive lenses can result from incorrect PD, improper fitting height, or excessive pantoscopic tilt, as all affect the progressive corridor alignment.

Question 24: Which frame adjustment corrects a frame that sits too close to the eyelashes on one side?

Increase the splay angle of the nose pad on the affected side (Correct answer)
Tighten the temple on the affected side
Bend the nose pad arm to move the pad outward on the opposite side
Decrease vertex distance on that side

Correct answer: Increase the splay angle of the nose pad on the affected side

Increasing the splay (flare) angle of the nose pad on the side where lashes touch pushes that side of the frame away from the face.

Question 25: State licensing requirements for opticians typically require which of the following?

Only passing the ABO exam with no state license required
Only completing an apprenticeship program without formal examination
Completion of an approved apprenticeship or educational program, passing an ABO/NCLE examination, and obtaining a state license (Correct answer)
Federal certification only; no state licensing exists for opticians

Correct answer: Completion of an approved apprenticeship or educational program, passing an ABO/NCLE examination, and obtaining a state license

Most states that license opticians require a combination of education/apprenticeship, ABO/NCLE examination passage, and a state license application with fees.

Question 26: What is the effect of increasing the pantoscopic tilt of a frame on the effective optical power experienced by the wearer?

It decreases both sphere and cylinder power
It has no effect on optical power
It only affects the add power in progressives
It increases effective sphere power and induces cylinder at the horizontal meridian (Correct answer)

Correct answer: It increases effective sphere power and induces cylinder at the horizontal meridian

Pantoscopic tilt tilts the optical axis downward, effectively increasing sphere power and inducing oblique cylinder.

Question 27: Which of the following would indicate that a lensometer needs recalibration?

A known plano lens reads a power other than zero (Correct answer)
The target moves when the patient lens is repositioned
The cylinder axis changes when rotating the lens
The target appears slightly yellow

Correct answer: A known plano lens reads a power other than zero

If a verified plano lens does not read zero on the lensometer, the instrument is out of calibration and must be adjusted.

Question 28: Which U.S. federal law protects patient health information, including prescriptions and vision records, held by eye care providers?

HIPAA (Health Insurance Portability and Accountability Act) (Correct answer)
OSHA regulations
ADA (Americans with Disabilities Act)
The Eyeglass Rule (FTC 16 CFR 456)

Correct answer: HIPAA (Health Insurance Portability and Accountability Act)

HIPAA's Privacy Rule protects individually identifiable health information. Eye care providers are covered entities that must protect patient records and prescriptions.

Question 29: The primary purpose of a lens clock (Geneva gauge) in dispensing is to:

Verify the prescription power written by the doctor
Check the frame's pantoscopic tilt angle
Measure the sagittal curve (base or front curve) of a lens surface (Correct answer)
Mark the optical center for edging

Correct answer: Measure the sagittal curve (base or front curve) of a lens surface

The lens clock measures the sagittal depth of a lens surface to determine its curvature (base curve), which is useful for matching replacement lenses.

Question 30: What is the primary purpose of a hard coat applied to plastic ophthalmic lenses?

Increase impact resistance
Improve scratch resistance (Correct answer)
Enhance anti-reflective properties
Reduce ultraviolet light transmission

Correct answer: Improve scratch resistance

Hard coats are applied to plastic lenses to improve scratch resistance, since most plastics are inherently softer than glass.

Question 31: What is the purpose of an 'edging allowance' when ordering a lens blank?

Additional blank diameter to ensure the prescription can be cut to fit the frame shape (Correct answer)
Extra power added for the reading zone
Prism added to account for frame wrap
UV coating applied to the edge of the lens

Correct answer: Additional blank diameter to ensure the prescription can be cut to fit the frame shape

The edging allowance ensures the blank is large enough so the prescription area extends fully to all edges of the traced frame shape.

Question 32: Which lens treatment reduces reflections on the lens surface by applying destructive interference coatings?

Photochromic treatment
Anti-reflective (AR) coating (Correct answer)
Hard coat
Polarized treatment

Correct answer: Anti-reflective (AR) coating

Anti-reflective (AR) coatings use thin-film interference to cancel out reflected light, reducing glare and improving light transmission.

Question 33: Under the FTC Contact Lens Rule, if a seller cannot reach the prescriber for verification, they may still dispense lenses if the prescriber fails to respond within:

4 business hours
24 business hours (Correct answer)
8 business hours
48 business hours

Correct answer: 24 business hours

Under the FTC Contact Lens Rule, a seller may dispense contact lenses if the prescriber fails to respond to a verification request within 8 business hours (or one business day).

Question 34: A prescription reads plano -2.50 x 160. What is its plus cylinder transposition?

plano +2.50 x 070
+2.50 -2.50 x 070
-2.50 +2.50 x 160
-2.50 +2.50 x 070 (Correct answer)

Correct answer: -2.50 +2.50 x 070

New sphere = 0.00 + (-2.50) = -2.50; new cyl = +2.50; new axis = 160 - 90 = 070.

Question 35: A prism with its apex pointing upward will deviate a light ray:

No deviation occurs
To the left
Toward the apex (upward)
Toward the base (downward) (Correct answer)

Correct answer: Toward the base (downward)

Light is always deviated toward the base of a prism, so an apex-up prism deflects rays downward.

Question 36: The optical cross is a diagram used to represent:

The prismatic effect of a lens
The vertex distance correction
The power in two principal meridians of a spherocylindrical lens (Correct answer)
The base curve and sag of a lens

Correct answer: The power in two principal meridians of a spherocylindrical lens

An optical cross shows the power in each of the two principal meridians (90° apart) of a spherocylindrical lens.

Question 37: What is the purpose of the segment height measurement in a bifocal or progressive lens fitting?

To determine the width of the reading segment
To position the near or reading zone at the correct height for the patient's gaze (Correct answer)
To set the pantoscopic tilt angle
To calculate the minimum blank size

Correct answer: To position the near or reading zone at the correct height for the patient's gaze

Segment height determines the vertical placement of the reading zone (bifocal seg top or progressive corridor start) relative to the pupil or lower lid.

Question 38: An object is placed 33 cm in front of a +4.00 D lens. Where does the image form?

50 cm behind the lens
100 cm behind the lens (Correct answer)
No real image forms
33 cm behind the lens

Correct answer: 100 cm behind the lens

Incoming vergence U = -1/0.33 = -3.00 D; V = P + U = 4.00 + (-3.00) = +1.00 D; image distance = 1/1.00 = 1.0 m = 100 cm behind the lens.

Question 39: The 'power error' in the context of spectacle lens aberrations refers to:

The difference between the paraxial power and the effective power at a peripheral lens zone (Correct answer)
An error in measuring the patient's prescription
The power lost due to anti-reflective coating
A manufacturing defect where the lens is made to the wrong power

Correct answer: The difference between the paraxial power and the effective power at a peripheral lens zone

Power error describes how the effective optical power experienced by the eye differs from the paraxial (central) power when gaze moves to the lens periphery.

Question 40: When adjusting metal frames, at what angle should the endpiece be set relative to the front to ensure proper temple alignment?

The temple should angle downward 10-15 degrees
The temple should extend straight back parallel to the ground (Correct answer)
The temple should angle upward 5 degrees
The temple should be bent inward toward the ear

Correct answer: The temple should extend straight back parallel to the ground

Properly adjusted temples should extend straight back from the hinge, parallel to the floor, before the earpiece bends over the ear.

Question 41: A stainless steel frame temple needs to be opened slightly for a wider head. The optician should:

Heat the temple with a frame warmer to 140°F before bending
Immerse the frame in boiling water for 30 seconds
Use temple-spreading pliers or gently spread the temple by hand at room temperature (Correct answer)
Score the metal lightly before bending to prevent cracking

Correct answer: Use temple-spreading pliers or gently spread the temple by hand at room temperature

Stainless steel is adjusted cold because heat is unnecessary and a torch could discolor or weaken the metal; gentle manual or plier pressure achieves the spread.

Question 42: The fovea centralis is important in opticianry because:

It contains the highest density of rod photoreceptors
It provides the highest visual acuity and is the target for optical center placement (Correct answer)
It is the entry point of the optic nerve into the eye
It detects peripheral motion and low-light vision

Correct answer: It provides the highest visual acuity and is the target for optical center placement

The fovea centralis contains the highest density of cone photoreceptors, providing maximum visual acuity. Optical centers should align with the line of sight to the fovea.

Question 43: Which federal agency regulates the labeling and marketing of prescription eyeglass frames in the United States?

The Food and Drug Administration (FDA)
The Federal Trade Commission (FTC) (Correct answer)
The Centers for Medicare & Medicaid Services (CMS)
The Occupational Safety and Health Administration (OSHA)

Correct answer: The Federal Trade Commission (FTC)

The FTC regulates advertising and marketing practices for eyeglass frames and related products to ensure truthful advertising and fair business practices.

Question 44: Transpose the following prescription into minus cylinder form: -3.00 +1.25 x 170

-4.25 +1.25 x 080
-1.75 +1.25 x 080
-1.75 -1.25 x 080 (Correct answer)
-3.00 -1.25 x 080

Correct answer: -1.75 -1.25 x 080

To transpose to minus cylinder, first find the new sphere by adding the sphere and cylinder (-3.00 + +1.25 = -1.75). Next, change the cylinder sign (+1.25 becomes -1.25). Finally, change the axis by 90 degrees (170 - 90 = 080).

Question 45: Transpose the prescription Plano +2.50 x 030 into minus cylinder form.

Plano -2.50 x 120
+2.50 +2.50 x 120
-2.50 +2.50 x 120
+2.50 -2.50 x 120 (Correct answer)

Correct answer: +2.50 -2.50 x 120

Start with the sphere (0.00) and add the cylinder (+2.50) to get the new sphere: +2.50. Change the cylinder sign to minus: -2.50. Change the axis by 90 degrees: 30 + 90 = 120. The result is +2.50 -2.50 x 120.

Question 46: When dispensing progressive addition lenses, the fitting cross should be positioned:

Directly over the pupil center in primary gaze (Correct answer)
2 mm above the pupil center in primary gaze
At the lower lid margin
4 mm below the pupil center in primary gaze

Correct answer: Directly over the pupil center in primary gaze

The fitting cross (MRP for the distance zone) is placed directly over the pupil in primary gaze to ensure proper corridor alignment.

Question 47: In ophthalmic lens terminology, what is the 'optical center' of a lens?

The point through which light passes without prismatic deviation (Correct answer)
The thickest point of a minus lens
The geometric center of the blank
The location of the reading addition in a bifocal

Correct answer: The point through which light passes without prismatic deviation

The optical center is the point on a lens through which a ray passes without being deviated by prism.

Question 48: In the boxing system of frame measurement, what does the 'A' measurement represent?

The horizontal width of the lens opening (eye size) (Correct answer)
The distance between the two lens openings
The vertical height of the lens opening
The effective diameter of the lens

Correct answer: The horizontal width of the lens opening (eye size)

In the boxing system, the 'A' measurement (eye size or lens width) is the horizontal width of the smallest rectangle that can fully contain the lens shape. It is one of the three key frame measurements (A, B, DBL) used to specify frame dimensions and calculate optical centration.

Question 49: The back vertex power of a lens differs most from its true power when:

The lens has low power
The lens is made of high-index material
The lens has high power and significant center thickness (Correct answer)
The lens is thin

Correct answer: The lens has high power and significant center thickness

Thick, high-powered lenses have the greatest difference between front vertex, back vertex, and true (equivalent) power.

Question 50: Hyperopia is corrected with which type of spectacle lens?

Concave (minus) lens
Cylindrical lens only
Convex (plus) lens (Correct answer)
Plano lens

Correct answer: Convex (plus) lens

Hyperopia (farsightedness) is an underpowered optical system corrected by adding converging power with a convex (plus) lens.

Question 51: The vitreous humor occupies approximately what percentage of the eye's total volume?

80% (Correct answer)
60%
40%
20%

Correct answer: 80%

The vitreous chamber makes up about 80% of the eye's total volume, with the vitreous being a gel-like substance filling it.

Question 52: Achromatic doublet lenses reduce chromatic aberration by:

Combining two lens elements with different Abbe values and powers (Correct answer)
Using a single high-index element
Applying a special anti-reflective coating
Increasing the lens center thickness

Correct answer: Combining two lens elements with different Abbe values and powers

An achromatic doublet pairs a crown glass element with a flint glass element of different Abbe values so their chromatic dispersions cancel each other.

Question 53: Retroscopic tilt (as opposed to pantoscopic tilt) means the top of the frame is:

Perfectly vertical
Tilted away from the face (Correct answer)
Tilted toward the face
Wrapped around the face

Correct answer: Tilted away from the face

Retroscopic tilt means the top of the frame front tilts away from the face, which is generally undesirable and reduces optical performance.

Question 54: A patient with presbyopia has difficulty with near vision primarily because of changes in which structure?

Crystalline lens (Correct answer)
Cornea
Vitreous humor
Retina

Correct answer: Crystalline lens

Presbyopia occurs when the crystalline lens loses elasticity with age, reducing the eye's ability to accommodate for near vision.

Question 55: Which of the following best describes a toric lens surface?

A surface that is perfectly flat
A surface with the same radius of curvature in all meridians
A surface with continuously varying power across the entire lens
A surface with two different principal radii of curvature at 90° to each other (Correct answer)

Correct answer: A surface with two different principal radii of curvature at 90° to each other

A toric surface has two principal meridians of different curvature oriented 90° apart, which is what creates the cylinder (astigmatic) correction.

Question 56: When transposing a minus-cylinder prescription to plus-cylinder form, the new axis is:

Original axis + 45°
Original axis − 45°
Original axis unchanged
Original axis ± 90° (Correct answer)

Correct answer: Original axis ± 90°

Transposition to the opposite cylinder form requires rotating the axis by 90 degrees.

Question 57: A photochromic lens darkens when exposed to UV radiation because of which mechanism?

The lens temperature increases, causing thermal darkening
UV radiation activates silver halide or organic molecules embedded in the lens, causing a color change (Correct answer)
An electronic sensor detects light intensity and adjusts tint electronically
A chemical reaction with visible light photons that changes dye molecular structure

Correct answer: UV radiation activates silver halide or organic molecules embedded in the lens, causing a color change

Photochromic lenses contain silver halide crystals or organic photochromic molecules that undergo a reversible chemical reaction when exposed to UV radiation, causing the lens to darken.

Question 58: CR-39 plastic lenses have a refractive index of approximately:

1.523
1.499 (Correct answer)
1.586
1.670

Correct answer: 1.499

CR-39 (Columbia Resin #39) has a refractive index of approximately 1.498–1.500, making it the standard plastic lens material.

Question 59: When verifying prescribed prism of 1.50Δ base in, ANSI Z80.1 allows a tolerance of:

±5% of prescribed amount
±0.25Δ (Correct answer)
±0.37Δ
±0.12Δ

Correct answer: ±0.25Δ

For prescribed prism of 2.00Δ or less, ANSI Z80.1 allows a tolerance of ±0.25Δ in any meridian.

Question 60: What is 'image jump' in a bifocal lens?

The change in apparent magnification between distance and near zones
The prismatic displacement of an image that occurs as the line of sight crosses the top edge of the bifocal segment (Correct answer)
The increase in add power as gaze moves downward into the segment
The chromatic aberration produced at the segment boundary

Correct answer: The prismatic displacement of an image that occurs as the line of sight crosses the top edge of the bifocal segment

Image jump is the sudden prismatic displacement of an object seen the instant the line of sight crosses the top of the bifocal segment. Its magnitude equals the add power multiplied by the distance (in cm) from the segment top to the segment's optical center, per Prentice's Rule.

Question 61: What happens to the critical angle when light travels from glass (n=1.5) into air (n=1.0)?

It increases as n increases
It equals 90°
It is approximately 41.8° (Correct answer)
No critical angle exists for this direction

Correct answer: It is approximately 41.8°

Using sin(c) = n2/n1 = 1.0/1.5, the critical angle for glass-to-air is approximately 41.8°.

Question 62: The radiuscope is used primarily to measure:

Vertex distance
Lens power in diopters
The radius of curvature of a contact lens back surface (Correct answer)
Pupillary distance

Correct answer: The radius of curvature of a contact lens back surface

The radiuscope measures the radius of curvature of contact lens surfaces, particularly the back (base) curve.

Question 63: Which step is performed LAST when transposing a prescription?

Rotate the axis 90° (Correct answer)
Change the cylinder sign
Record the new sphere
Add sphere and cylinder

Correct answer: Rotate the axis 90°

The final step of transposition is rotating the axis by 90° (add or subtract 90, keeping result between 1 and 180).

Question 64: A lens with a base curve of +6.00 D and a back surface of −3.50 D has an approximate power of:

+3.50 D
+6.00 D
+9.50 D
+2.50 D (Correct answer)

Correct answer: +2.50 D

Approximate lens power ≈ front surface + back surface = +6.00 + (−3.50) = +2.50 D.

Question 65: A flat-top 28 bifocal has an add power of +2.50 D. The segment OC is 5 mm below the segment top. What is the amount of image jump?

0 prism diopters
0.50 prism diopters
2.50 prism diopters
1.25 prism diopters (Correct answer)

Correct answer: 1.25 prism diopters

Using Prentice's Rule: P = F × d = 2.50 × 0.5 cm = 1.25 prism diopters. The distance d is 5 mm (0.5 cm) from the segment top to the segment OC, and F is the add power. This base-down prism causes the image to jump upward as gaze enters the segment.

Question 66: An optician in a state without a specific law defining the expiration date for spectacle prescriptions receives a valid prescription from a new patient. According to the federal FTC Eyeglass Rule, what is the minimum length of time for which this prescription must be considered valid?

It is left entirely to the professional judgment of the dispensing optician.
One year from the date of the examination. (Correct answer)
Two years from the date of the examination.
Six months from the date of the examination.

Correct answer: One year from the date of the examination.

The FTC Eyeglass Rule stipulates that if state law does not define an expiration date, a spectacle prescription shall be valid for not less than one year. An optometrist or ophthalmologist may set a shorter expiration date if there is a specific medical reason, which should be documented. Contact lens prescriptions, governed by a different rule, typically have a minimum one-year expiration.

Question 67: The Geneva lens gauge (lens clock) measures:

The total lens power in diopters
The frame PD
The surface power (base curve) of a lens surface (Correct answer)
The lens thickness at the center

Correct answer: The surface power (base curve) of a lens surface

The Geneva lens gauge (lens clock) measures the surface curvature (surface power) of a lens, allowing calculation of the approximate power of each surface.

Question 68: A patient returns with a metal frame whose nose pads are pressing unevenly. The correct first step is to:

Advise the patient this cannot be adjusted
Heat the bridge area with a flame to soften the metal
Replace the nose pads entirely
Use pad-adjusting pliers to reposition the pad arms symmetrically (Correct answer)

Correct answer: Use pad-adjusting pliers to reposition the pad arms symmetrically

Pad-adjusting pliers allow precise repositioning of metal pad arms to achieve symmetrical, even pressure without damaging the frame.

Question 69: What does the term 'specific gravity' refer to when describing lens materials?

The refractive index of the material
The density of a material relative to water (Correct answer)
The impact resistance score
The scratch resistance rating

Correct answer: The density of a material relative to water

Specific gravity is the ratio of the material's density to that of water, and it determines the weight of the finished lens.

Question 70: A frame with a 'wrap' style has a face form angle of 15 degrees. How does this affect the effective power of a prescription lens?

It increases the prismatic effect at the optical center
It induces unwanted cylinder and changes the effective sphere power (Correct answer)
It decreases the vertex distance only
It only affects the cosmetic appearance of the lens

Correct answer: It induces unwanted cylinder and changes the effective sphere power

Face form (pantoscopic tilt and wrap angle) causes off-axis viewing through the lens, inducing unwanted oblique astigmatism that must be compensated in the prescription.

Question 71: A patient completes their eye exam, pays for the service, and asks for a copy of their spectacle prescription to take with them. The office policy is to only release prescriptions to patients who purchase eyewear from the in-house optical. According to the FTC Eyeglass Rule, what is the legal obligation of the prescriber?

They must provide the patient with a copy of their prescription immediately after the exam, without requiring a purchase. (Correct answer)
They can charge a reasonable fee for providing a paper copy of the prescription.
They are only required to release the prescription directly to another optical dispenser, not to the patient.
They can withhold the prescription until the patient agrees to look at their frame selection.

Correct answer: They must provide the patient with a copy of their prescription immediately after the exam, without requiring a purchase.

The Federal Trade Commission (FTC) Eyeglass Rule requires prescribers to give patients their prescription immediately after an eye exam is complete. The rule prohibits conditioning the release of a prescription on the patient's agreement to purchase eyewear from the prescriber and forbids charging an additional fee for the prescription itself.

Question 72: Which of the following lens material properties is most directly associated with the amount of transverse chromatic aberration a patient is likely to experience?

UV Attenuation
Specific Gravity
Index of Refraction
Abbe Value (Correct answer)

Correct answer: Abbe Value

The Abbe value is a measure of a lens material's chromatic dispersion. A lower Abbe value indicates higher dispersion, which causes more chromatic aberration (color fringing), especially when viewing off-axis. Materials with a higher Abbe value have less dispersion and therefore cause less chromatic aberration.

Question 73: A state with 'title only' opticianry laws means that:

Only licensed individuals may perform any optical work in the state
Opticians must hold both ABO and NCLE certifications
Opticians are exempt from all federal regulations
Only the title 'optician' is restricted, but the work may be performed by unlicensed individuals (Correct answer)

Correct answer: Only the title 'optician' is restricted, but the work may be performed by unlicensed individuals

Title-only protection laws restrict who may call themselves an 'optician' but do not prohibit unlicensed persons from performing optical dispensing work.

Question 74: According to the ANSI Z80.1-2020 standard, what is the tolerance for sphere power on a finished single vision lens with a power of -4.50 D?

± 0.13 D (Correct answer)
± 0.25 D
± 0.18 D
± 0.09 D

Correct answer: ± 0.13 D

The ANSI Z80.1-2020 standard specifies a tolerance of ±0.13 D for sphere powers between +6.50 D and -6.50 D. Since -4.50 D falls within this range, this is the acceptable tolerance.

Question 75: Which instrument is used to measure the base curve of a finished lens?

Radiuscope
Geneva lens clock (Correct answer)
Lensometer
Focimeter

Correct answer: Geneva lens clock

The Geneva lens clock (lens measure) is used at the dispensing level to measure the surface curves of a finished lens.

Question 76: Which entity has primary authority for licensing opticians at the state level in the United States?

The American Board of Opticianry (ABO)
The FTC
The state board of optometry or opticianry (Correct answer)
The FDA

Correct answer: The state board of optometry or opticianry

Opticianry licensing is a state function, administered by each state's board of optometry, opticianry, or a combined health professions board.

Question 77: An optician finds 1.80Δ of induced prism in a -4.50 D lens. How far is the OC displaced from the MRP?

4 mm (Correct answer)
0.4 mm
8.1 mm
2.5 mm

Correct answer: 4 mm

d = 1.80/4.50 = 0.4 cm = 4 mm.

Question 78: What is the primary reason TR-90 (nylon-based) frames require a different adjustment approach than standard acetate?

TR-90 expands significantly when warmed, distorting the frame shape
TR-90 melts at a lower temperature than acetate
TR-90 cannot be adjusted at all and must be remade
TR-90 has high flexibility and memory, resisting permanent deformation from heat alone (Correct answer)

Correct answer: TR-90 has high flexibility and memory, resisting permanent deformation from heat alone

TR-90's nylon composition gives it spring-like memory, meaning adjustments may need more force and the frame may partially revert, requiring patient counseling about limitations.

Question 79: When neutralizing a lens using loose trial lenses, the lens is considered neutralized when:

No movement (scissors motion) is seen through the combined lens system (Correct answer)
The lens and trial lens create equal and opposite prism
The image through the lens appears magnified
The 'against' motion of the test lens is observed

Correct answer: No movement (scissors motion) is seen through the combined lens system

Neutralization is complete when the combined lens and trial lens produce no movement of the observed target—indicating equal and opposite powers.

Question 80: What is the index of refraction of a material if light travels through it at 2.0 × 10⁸ m/s (speed of light in air = 3.0 × 10⁸ m/s)?

1.33
0.67
2.00
1.50 (Correct answer)

Correct answer: 1.50

Index of refraction n = speed of light in air / speed of light in medium = 3.0/2.0 = 1.50.

Question 81: A lens has a power of +3.00 D. What is its focal length?

3.0 cm
300 cm
0.33 cm
33.3 cm (Correct answer)

Correct answer: 33.3 cm

Focal length (in meters) = 1 / Power. 1 / 3.00 = 0.333 m = 33.3 cm.

Question 82: Which lens material has the highest Abbe value among commonly used ophthalmic lens materials?

High-index 1.74
Trivex
Polycarbonate
Crown glass (Correct answer)

Correct answer: Crown glass

Crown glass (ophthalmic crown) has the highest Abbe value of approximately 58, meaning it produces the least chromatic aberration.

Question 83: What is the recommended method for heating an Optyl frame for adjustment?

No heat is required; it is adjusted cold.
A hot air frame warmer (Correct answer)
Hot running water
A hot salt pan

Correct answer: A hot air frame warmer

Optyl is a thermosetting epoxy resin with a 'memory effect.' It requires uniform heating to around 80-120°C (176-248°F) to become pliable. A hot air warmer is the ideal tool, as a salt pan can cause overheating and damage the material's surface and properties.

Question 84: Transpose -3.00 +1.50 x 090 into minus cylinder form.

-1.50 -1.50 x 180 (Correct answer)
-3.00 -1.50 x 090
-4.50 +1.50 x 090
-1.50 +1.50 x 180

Correct answer: -1.50 -1.50 x 180

New sphere = -3.00 + 1.50 = -1.50; new cylinder = -1.50; new axis = 090 + 90 = 180.

Question 85: Which tool is used to measure the segment height for a bifocal lens?

Pupillometer
Millimeter ruler or segometer held while the patient wears the frame (Correct answer)
Lensmeter
Distometer

Correct answer: Millimeter ruler or segometer held while the patient wears the frame

Segment height is measured with a millimeter ruler or segometer while the patient wears the correctly adjusted frame and looks straight ahead.

Question 86: The Americans with Disabilities Act (ADA) requires optical retailers with 15 or more employees to:

Stock ADA-compliant frame styles
Provide free eyewear to disabled customers
Make reasonable accommodations for qualified employees with disabilities (Correct answer)
Offer low vision services on site

Correct answer: Make reasonable accommodations for qualified employees with disabilities

The ADA requires covered employers (15+ employees) to provide reasonable accommodations to qualified individuals with disabilities.

Question 87: When dispensing progressive addition lenses (PALs), the fitting cross should be positioned:

4 mm above the pupil center
At the center of the pupil when the patient looks straight ahead in natural primary gaze (Correct answer)
At the lower pupil margin
At the top of the patient's iris

Correct answer: At the center of the pupil when the patient looks straight ahead in natural primary gaze

The progressive lens fitting cross (or fitting point) must align with the pupil center in primary gaze to ensure the patient looks through the correct zone of the lens for each distance.

Question 88: A patient's prescription is -8.00 DS. Which lens material would BEST minimize edge thickness?

High-index 1.67
CR-39 (n=1.50)
High-index 1.74 (Correct answer)
Polycarbonate (n=1.586)

Correct answer: High-index 1.74

High-index 1.74 has the highest index of refraction among common ophthalmic materials, bending light most efficiently and producing the thinnest lenses for high minus prescriptions.

Question 89: A patient presents with a sudden shower of floaters and flashes of light. The optician should immediately refer for evaluation of which condition?

Presbyopia
Dry eye syndrome
Cataract
Retinal detachment (Correct answer)

Correct answer: Retinal detachment

Sudden floaters and photopsia (flashes) are classic warning signs of posterior vitreous detachment or retinal tear/detachment requiring urgent evaluation.

Question 90: When a patient's glasses cause a red mark on the nose, the best immediate adjustment is to:

Widen the nose pad spread (Correct answer)
Lower the temples
Tighten the frame front
Increase the pantoscopic tilt

Correct answer: Widen the nose pad spread

Widening the nose pad spread distributes the frame weight over a larger area, reducing pressure that causes red marks.

Question 91: What is the dioptric power of a surface with a radius of curvature of 0.10 m separating air (n=1.0) from glass (n=1.5)?

+1.50 D
+0.50 D
+5.00 D (Correct answer)
+10.00 D

Correct answer: +5.00 D

Surface power = (n2 - n1) / r = (1.5 - 1.0) / 0.10 = 0.5 / 0.10 = +5.00 D.

Question 92: The reduced eye model simplifies the eye to a single refracting surface with a refractive index of approximately:

1.336 (Correct answer)
1.760
1.523
1.000

Correct answer: 1.336

The reduced eye model uses a single refracting surface with the refractive index of the ocular media, approximately 1.336.

Question 93: A lens has a power of +3.00 D. A patient's pupil is decentered 4 mm below the optical center. How much vertical prism is induced?

1.20Δ base down
0.75Δ base down
1.20Δ base up (Correct answer)
0.75Δ base up

Correct answer: 1.20Δ base up

Δ = P × d = 3.00 × 0.4 = 1.20Δ; looking below the OC of a plus lens produces base-up prism because the prism base points toward the OC.

Question 94: When measuring a lens with the lensometer, moving the lens to the right causes the target to move to the left. This relationship tells you that:

The lens has cylinder power
The lens has minus power (Correct answer)
The lens has plus power
The lens has no power

Correct answer: The lens has minus power

When moving a lens causes the target to move in the opposite direction (against motion), the lens has minus (concave) power.

Question 95: What is the purpose of a lenticular lens design in high-power prescriptions?

To increase the field of view
To increase chromatic aberration
To eliminate the need for anti-reflective coating
To reduce lens weight and thickness by limiting the optical zone (Correct answer)

Correct answer: To reduce lens weight and thickness by limiting the optical zone

Lenticular designs place full prescription power only in a central optical zone, reducing overall lens weight and thickness for high-power corrections.

Question 96: According to ANSI Z80.1, for a prescription with sphere power of -5.00 D and no cylinder, what is the allowed power tolerance?

±0.50 D
±0.06 D
±0.12 D (Correct answer)
±0.25 D

Correct answer: ±0.12 D

ANSI Z80.1 allows a power tolerance of ±0.12 D for lenses with a vertex power exceeding 3.37 D in the meridian being tested.

Question 97: What is the spherical equivalent of the prescription -3.00 -2.00 x 180?

-2.50 D
-3.50 D
-3.00 D
-4.00 D (Correct answer)

Correct answer: -4.00 D

Spherical equivalent (SE) = sphere + (cylinder ÷ 2) = -3.00 + (-2.00 ÷ 2) = -3.00 + (-1.00) = -4.00 D. The spherical equivalent represents the single sphere power that most closely approximates the mean refractive effect of a sphero-cylindrical lens.

Question 98: What is 'lens clock' (lens measure) used to measure?

The segment height on a bifocal
The optical center height
The lens diameter
The surface curvature (base curve) of a lens surface (Correct answer)

Correct answer: The surface curvature (base curve) of a lens surface

A lens clock (lens measure) measures the surface power/curvature of a lens by sensing the sagittal depth across a fixed chord.

Question 99: An optician needs to make a significant adjustment to a thick zyl (cellulose acetate) frame temple. Which tool provides the most uniform and safest heat to make the material pliable without causing localized overheating or bubbling?

A handheld butane torch
A salt pan with glass beads (Correct answer)
A high-velocity hot air blower
A hot water bath

Correct answer: A salt pan with glass beads

A salt pan, typically filled with glass beads or fine salt, provides gentle and even heat across the entire portion of the frame being adjusted. This uniformity is crucial for thick acetate frames to prevent damage like bubbling or warping, which can occur with the concentrated heat from a hot air blower or other methods.

Question 100: The aqueous humor is produced by the:

Ciliary body (ciliary processes) (Correct answer)
Corneal endothelium
Lacrimal gland
Trabecular meshwork

Correct answer: Ciliary body (ciliary processes)

The ciliary processes of the ciliary body secrete aqueous humor, which fills the anterior and posterior chambers and maintains intraocular pressure.

Question 101: According to ANSI Z80.1 standards, what is the allowable tolerance for the add power of a progressive lens up to +4.00 D add?

+/- 0.18 D
+/- 0.12 D
+/- 0.50 D
+/- 0.25 D (Correct answer)

Correct answer: +/- 0.25 D

ANSI Z80.1 allows a +/- 0.25 D tolerance for the add power on progressive lenses with adds up to +4.00 D.

Question 102: A patient's right eye requires 1.50Δ base in. The lens power is +3.00 D. In which direction and how far should the optical center be decentered?

5 mm nasally (Correct answer)
0.5 mm nasally
0.5 mm temporally
5 mm temporally

Correct answer: 5 mm nasally

d = 1.50/3.00 = 0.5 cm = 5 mm; for a plus lens, decentering the OC nasally places the eye temporal to the OC, inducing base-in prism.

Question 103: A frame's distance between boxing centers is 70 mm. Patient binocular PD is 62 mm. Lens power is -2.00 D; decentration is split equally. What prism is induced per eye?

1.60Δ
0.16Δ
0.80Δ (Correct answer)
0.40Δ

Correct answer: 0.80Δ

Total decentration = 70 - 62 = 8 mm; per eye = 4 mm = 0.4 cm; Δ = 2.00 × 0.4 = 0.80Δ per eye.

Question 104: A finished pair of single vision glasses is inspected and found to have a vertical prism imbalance of 0.50Δ between the right and left lenses. According to the ANSI Z80.1-2020 standard, does this pair of glasses meet the tolerance for vertical prism?

Yes, the tolerance is up to 1.00Δ.
No, the standard requires an absolute zero vertical imbalance.
No, the tolerance for vertical prism is a maximum of 0.33Δ. (Correct answer)
Yes, the tolerance is up to 0.67Δ.

Correct answer: No, the tolerance for vertical prism is a maximum of 0.33Δ.

The ANSI Z80.1-2020 standard for prescription ophthalmic lenses states that the tolerance for vertical prismatic imbalance between a pair of mounted single vision or multifocal lenses shall not exceed 0.33Δ (one-third of a prism diopter). An imbalance of 0.50Δ is outside this acceptable tolerance.

Question 105: An optician in a state that requires licensure practices without a current license. This is considered:

A minor administrative infraction
Unlicensed practice, which is illegal (Correct answer)
Acceptable if supervised by a licensed optometrist
Practicing within a grace period

Correct answer: Unlicensed practice, which is illegal

Practicing opticianry without a required state license constitutes unlicensed practice, which is illegal and subject to penalties.

Question 106: When light passes from a denser medium to a less dense medium at an angle exceeding the critical angle, what occurs?

Refraction
Diffraction
Dispersion
Total internal reflection (Correct answer)

Correct answer: Total internal reflection

Total internal reflection occurs when light exceeds the critical angle at the boundary between a denser and less dense medium.

Question 107: The standard vertex distance used when prescribing trial frame refraction is:

16mm
14mm
12mm (Correct answer)
10mm

Correct answer: 12mm

The standard vertex distance for trial frame refraction is 12mm, and prescriptions are compensated if the actual vertex distance differs significantly.

Question 108: What does a pupilometer measure, and what advantage does it have over a PD ruler?

It measures the vertex distance; it eliminates the need for a ruler
It measures pupillary distance; it provides more accurate monocular PD measurements with less parallax error (Correct answer)
It measures near PD; it automatically compensates for convergence
It measures pupil diameter; it gives more accurate refraction results

Correct answer: It measures pupillary distance; it provides more accurate monocular PD measurements with less parallax error

A pupilometer measures pupillary distance more accurately than a PD ruler by directly viewing the pupils through an optical system, reducing parallax error, and providing monocular measurements.

Question 109: What is the add power for a patient whose distance Rx is +1.00 D and near Rx is +3.00 D?

-2.00 D
+4.00 D
+1.00 D
+2.00 D (Correct answer)

Correct answer: +2.00 D

Add power = near Rx minus distance Rx = +3.00 − (+1.00) = +2.00 D.

Question 110: A screwdriver used in optical frame repair should have which tip to avoid stripping tiny eyeglass screws?

A large flat-blade screwdriver tip
An Allen (hex) key
A precision flat-blade or JIS tip sized specifically for optical screws (Correct answer)
A Phillips #3 head

Correct answer: A precision flat-blade or JIS tip sized specifically for optical screws

Optical screws are very small and require precision flat-blade or JIS screwdrivers matched to the screw head size to avoid stripping.

Question 111: A lens is +2.00 -4.00 × 090. A patient looks through a point 4 mm temporal to the OC in the right eye. What is the horizontal prismatic effect?

0.80Δ base out
1.60Δ base in
0.80Δ base in (Correct answer)
0.40Δ base out

Correct answer: 0.80Δ base in

Axis 090 means the cylinder acts in the 180° (horizontal) meridian; horizontal power = +2.00 + (-4.00) = -2.00 D; Δ = 2.00 × 0.4 = 0.80Δ; minus lens with OC nasal to gaze = base in.

Question 112: Which refractive error is caused by the cornea or lens having different curvatures in different meridians?

Hyperopia
Presbyopia
Myopia
Astigmatism (Correct answer)

Correct answer: Astigmatism

Astigmatism occurs when the eye's refracting surfaces (usually the cornea) have different powers in different meridians, causing light to focus in two separate focal lines instead of a single point.

Question 113: Which layer of the cornea constitutes approximately 90% of its thickness and is composed of highly organized collagen fibrils that are crucial for maintaining corneal transparency?

Bowman's Layer
Epithelium
Endothelium
Stroma (Correct answer)

Correct answer: Stroma

The stroma is the thickest layer of the cornea, making up about 90% of its total thickness. Its structure consists of regularly arranged collagen fibers and keratocytes, which is essential for the cornea's strength and transparency. Disruption to this organized arrangement can lead to light scattering and reduced visual clarity.

Question 114: Which characteristic of a sunglass lens is described by the term 'luminous transmittance'?

The ability of the lens to reduce glare
The percentage of UV light blocked by the lens
The percentage of visible light that passes through the lens (Correct answer)
The warmth of the lens tint color

Correct answer: The percentage of visible light that passes through the lens

Luminous transmittance is the ratio of the luminous flux transmitted through a lens to the incident luminous flux — essentially what percentage of visible light passes through.

Question 115: When using a lensometer to verify a progressive lens, where should the distance power be measured?

Through the distance reference point (DRP) or distance zone (Correct answer)
At the fitting cross
At the geometric center of the lens
At the prism reference point (PRP)

Correct answer: Through the distance reference point (DRP) or distance zone

Distance power is verified through the distance reference point (DRP) or the distance zone of a progressive lens, not the geometric center.

Question 116: In ophthalmic optics, what does the term 'transposition' refer to?

Converting plus cylinder form to minus cylinder form (or vice versa) (Correct answer)
Adjusting pantoscopic tilt
Rotating the axis of a cylinder lens
Changing the base curve of a lens

Correct answer: Converting plus cylinder form to minus cylinder form (or vice versa)

Transposition is the mathematical process of rewriting a prescription from plus cylinder form to minus cylinder form or vice versa without changing its optical effect.

Question 117: A patient's zyl (acetate) frame shows whitening at a bend point after adjustment. This indicates:

The frame needs a second round of heating to set the adjustment
The material was bent while too cool, causing stress fractures (Correct answer)
The acetate has oxidized and needs polishing
The frame was adjusted correctly and color will return

Correct answer: The material was bent while too cool, causing stress fractures

Whitening or stress marks in acetate indicate the material was bent cold or at an insufficient temperature, creating micro-fractures in the plastic.

Question 118: Which pupillary distance (PD) measurement is required when dispensing single-vision lenses?

Distance PD only
Near PD only
Both monocular distance and near PD
Monocular distance PD for each eye (Correct answer)

Correct answer: Monocular distance PD for each eye

Monocular PDs (right and left separately) are required to correctly center each single-vision lens over its respective pupil.

Question 119: A patient presents with sudden onset of halos around lights, eye pain, nausea, and blurred vision. This presentation is most consistent with:

Acute angle-closure glaucoma (Correct answer)
Cataract
Open-angle glaucoma
Dry eye syndrome

Correct answer: Acute angle-closure glaucoma

Acute angle-closure glaucoma presents with sudden severe eye pain, halos, nausea/vomiting, and rapidly increasing IOP. This is an ocular emergency requiring immediate referral.

Question 120: What does the term 'decentration' refer to in opticianry?

Moving the optical center away from the pupil center (Correct answer)
Increasing the pantoscopic tilt
Adjusting the vertex distance
Changing the lens base curve

Correct answer: Moving the optical center away from the pupil center

Decentration is the intentional horizontal or vertical displacement of the optical center relative to the frame's geometric center.

Question 121: Transposing the prescription +3.50 -2.00 × 045 to plus-cylinder form gives:

+1.50 +2.00 × 135 (Correct answer)
+5.50 -2.00 × 135
+1.50 +2.00 × 045
+3.50 +2.00 × 135

Correct answer: +1.50 +2.00 × 135

To transpose to plus cylinder: new sphere = old sphere + old cylinder = +3.50 + (-2.00) = +1.50. New cylinder = -old cylinder = +2.00. New axis = old axis ± 90° = 045 + 90° = 135°.

Question 122: A patient's PD is 64 mm, but their glasses were made with the optical centers at 60 mm. If the Rx is -5.00 DS in both eyes, what is the total induced prism?

1.0Δ Base In
2.0Δ Base In
1.0Δ Base Out
2.0Δ Base Out (Correct answer)

Correct answer: 2.0Δ Base Out

The total decentration is 4 mm, or 2 mm per eye. The OCs are too narrow, so they are decentered nasally. P = cF = (0.2 cm) * (5.00 D) = 1.0Δ per eye. For a minus lens, nasal decentration creates Base Out prism. The total is 1.0Δ BO + 1.0Δ BO = 2.0Δ BO.

Question 123: A low-to-moderate hyperope who does NOT wear correction will typically experience which of the following?

Potentially clear vision at distance and near by using accommodation, but with eye strain (Correct answer)
Blurred distance vision, clear near vision
Equal blur at all distances with no eye strain
Clear distance vision, blurred near vision at all times

Correct answer: Potentially clear vision at distance and near by using accommodation, but with eye strain

Low-to-moderate hyperopes can use their accommodative reserve to compensate, achieving acceptable vision at both distance and near — but at the cost of chronic accommodative effort that leads to asthenopia (headaches, eye strain). High hyperopes eventually cannot fully compensate and experience blur at all distances.

Question 124: Which muscle controls the width of the pupil in bright light conditions?

Superior oblique
Sphincter pupillae (Correct answer)
Ciliary muscle
Dilator pupillae

Correct answer: Sphincter pupillae

The sphincter pupillae is a circular muscle innervated by parasympathetic fibers that constricts the pupil (miosis) in bright light.

Question 125: Which type of lensometer reticle pattern uses a bullseye (circle with cross) target?

Prism verification pattern
European pattern with cross-hair only
Progressive lens pattern
American Standard (ANSI) pattern (Correct answer)

Correct answer: American Standard (ANSI) pattern

The American Standard lensometer uses a bullseye target with concentric circles and crossed lines to allow simultaneous sphere, cylinder, and prism measurement.

Question 126: Which surface of a meniscus lens is typically convex?

Both surfaces are convex
Neither surface is convex
The back (ocular) surface
The front (object-side) surface (Correct answer)

Correct answer: The front (object-side) surface

In a standard ophthalmic meniscus lens, the front (convex) surface curves toward the world and the back (concave) surface curves toward the eye.

Question 127: When measuring the segment height for a patient being fitted with a Flat-Top 28 (FT-28) bifocal, which of the following landmarks is the standard reference point to measure to?

The center of the pupil.
The upper edge of the lower eyelid. (Correct answer)
A point 3 mm below the pupil center.
The lower limbus (edge of the iris).

Correct answer: The upper edge of the lower eyelid.

The standard fitting protocol for a flat-top (or straight-top) bifocal is to measure from the deepest part of the lens bevel in the frame up to the patient's lower eyelid margin. This placement ensures the reading segment is just out of the way for distance viewing but easily accessible when the wearer drops their eyes to read.

Question 128: What is 'retroscopic tilt' and how does it affect the patient?

The top of the frame tilting toward the face (reverse of pantoscopic); it can cause unwanted oblique astigmatism and visual distortion (Correct answer)
The angle of the temples relative to the frame front
The frame tilting too far forward at the top (same as pantoscopic tilt)
A horizontal misalignment of the frame on the face

Correct answer: The top of the frame tilting toward the face (reverse of pantoscopic); it can cause unwanted oblique astigmatism and visual distortion

Retroscopic tilt (negative pantoscopic tilt) is when the top of the lens tilts toward the face. It induces unwanted astigmatic power and should be avoided.

Question 129: A patient with polycarbonate lenses (-5.00 D) complains of rainbow-colored fringes around car headlights at night. The dispenser should explain that this is caused by:

High-index lens thickness creating interference patterns
Scratches on the lens surface diffracting light
The anti-reflective coating breaking down
The low Abbe value (approximately 30) of polycarbonate causing chromatic aberration (Correct answer)

Correct answer: The low Abbe value (approximately 30) of polycarbonate causing chromatic aberration

Polycarbonate's low Abbe value of about 30 causes significant chromatic dispersion, producing colored fringes, especially noticeable with point light sources at night.

Question 130: Under OSHA regulations, opticianry labs that use hazardous chemicals must provide employees with access to:

Personal protective equipment only
Written proof of chemical disposal
Annual chemical exposure testing only
Safety Data Sheets (SDS) for all hazardous materials (Correct answer)

Correct answer: Safety Data Sheets (SDS) for all hazardous materials

OSHA's Hazard Communication Standard requires that Safety Data Sheets be readily accessible to employees for every hazardous chemical in the workplace.

Question 131: What is the purpose of a 'lenticular' lens design?

To provide a multifocal correction without a visible segment line
To reduce weight and thickness in very high-power prescriptions by limiting the full-power zone to a central optical cap (Correct answer)
To maximize the field of view by using an aspheric periphery
To provide a built-in prism for strabismus correction

Correct answer: To reduce weight and thickness in very high-power prescriptions by limiting the full-power zone to a central optical cap

Lenticular lenses have a central optical portion (the lenticular bowl or cap) containing the full prescription power, surrounded by a carrier of reduced power, dramatically reducing weight and thickness for very high prescriptions.

Question 132: Transpose the following prescription into plus cylinder form: +1.50 -2.00 x 090

-0.50 +2.00 x 180 (Correct answer)
+1.50 +2.00 x 180
-0.50 -2.00 x 180
+3.50 -2.00 x 180

Correct answer: -0.50 +2.00 x 180

To transpose, first combine the sphere and cylinder powers to get the new sphere (+1.50 + -2.00 = -0.50). Second, change the sign of the cylinder (-2.00 becomes +2.00). Third, change the axis by 90 degrees (90 + 90 = 180).

Question 133: The power cross for -1.00 DS shows which values in both meridians?

-1.00 in one and 0.00 in the other
+1.00 in one meridian only
-1.00 in both meridians (Correct answer)
0.00 in both meridians

Correct answer: -1.00 in both meridians

A spherical lens (DS) has the same power in every meridian, so both principal meridians on the power cross read -1.00.

Question 134: What is the power cross for the prescription +2.00 -1.50 × 090?

+2.00 D at 090 and +0.50 D at 180
+0.50 D at 090 and +2.00 D at 180 (Correct answer)
+2.00 D at 090 and -1.50 D at 180
-1.50 D at 090 and +2.00 D at 180

Correct answer: +0.50 D at 090 and +2.00 D at 180

The axis is 090, so no cylinder acts at 090. Power at 090 = sphere = +2.00 + 0 = +2.00. Wait — at axis 090, cylinder = 0, so power = +2.00. At 180 (perpendicular to axis), power = +2.00 + (-1.50) = +0.50.

Question 135: Which of the following instruments directly measures the sagittal depth of a lens curve to determine its surface power?

Distometer
Lensometer
Pupilometer
Lens Clock (Correct answer)

Correct answer: Lens Clock

A lens clock, also known as a lens gauge or spherometer, is a mechanical instrument with three pins. The central pin moves, and its displacement relative to the two fixed outer pins measures the sagittal depth (or sag) of a lens curve. The dial on the instrument is calibrated to convert this sagittal depth measurement into a dioptric surface power, typically based on the refractive index of crown glass.

Question 136: What is the primary optical aberration corrected by aspheric lens designs?

Spherical aberration (Correct answer)
Distortion
Coma
Chromatic aberration

Correct answer: Spherical aberration

Aspheric lens designs flatten the lens surface progressively from center to edge to reduce spherical aberration.

Question 137: An optician uses a digital caliper during the dispensing process primarily to:

Precisely measure lens thickness, frame dimensions, or segment heights in millimeters (Correct answer)
Measure pupillary distance
Determine the optical center of a lens
Measure corneal curvature

Correct answer: Precisely measure lens thickness, frame dimensions, or segment heights in millimeters

Digital calipers provide precise millimeter measurements of lens thickness, frame component dimensions, and other critical physical parameters during dispensing.

Question 138: A patient reports that rectangular doorframes appear to bow outward (barrel-shaped) when wearing new glasses. This is consistent with which aberration and prescription type?

Pincushion distortion from a plus lens
Barrel distortion from a minus lens (Correct answer)
Field curvature from an aspheric lens
Coma from a high-index lens

Correct answer: Barrel distortion from a minus lens

Barrel distortion, where straight lines bow outward, is characteristic of minus (concave) lenses.

Question 139: OSHA's Bloodborne Pathogens Standard most directly applies to optical dispensaries when:

Adjusting metal frames on a patient
Handling a broken lens that cuts an employee (Correct answer)
Processing insurance claims
Ordering stock from a supplier

Correct answer: Handling a broken lens that cuts an employee

OSHA's Bloodborne Pathogens Standard applies when employees may be exposed to blood or other potentially infectious materials, such as from a cut during frame or lens handling.

Question 140: Photochromic lenses darken when exposed to UV light because they contain:

A liquid crystal layer that polarizes in sunlight
Silver halide crystals (glass) or organic photochromic molecules (plastic) that undergo a reversible chemical reaction when exposed to UV (Correct answer)
A permanent tint that darkens with heat
Reflective coatings that block UV

Correct answer: Silver halide crystals (glass) or organic photochromic molecules (plastic) that undergo a reversible chemical reaction when exposed to UV

Glass photochromics use silver halide crystals; plastic photochromics (like Transitions) use organic naphthopyran molecules. Both undergo a reversible photochemical reaction that causes darkening when UV-exposed.

Question 141: Intraocular pressure (IOP) is measured with which instrument, and what is the normal range?

Keratometer; normal range is 8–15 mmHg
Tonometer; normal range is 10–21 mmHg (Correct answer)
Biomicroscope; normal range is 15–25 mmHg
Lensometer; normal range is 10–21 mmHg

Correct answer: Tonometer; normal range is 10–21 mmHg

IOP is measured with a tonometer (applanation or non-contact type). Normal IOP is 10–21 mmHg; elevated IOP is a major glaucoma risk factor.

Question 142: A patient's prescription is OD -4.00 -1.50 x 090. What is the power in the 180 meridian?

-2.50 D
-5.50 D (Correct answer)
-1.50 D
-4.00 D

Correct answer: -5.50 D

In a minus-cylinder prescription, the sphere power acts along the axis meridian (090), and the full cylinder power is added 90° away (180°): -4.00 + (-1.50) = -5.50 D.

Question 143: Which type of lens corrects myopia (nearsightedness)?

Plus (convex) lens
Prism lens
Minus (concave) lens (Correct answer)
Plano lens

Correct answer: Minus (concave) lens

Myopia results from light focusing in front of the retina. A minus (diverging) lens moves the focal point back to the retina.

Question 144: Which law states that the angle of incidence equals the angle of reflection?

Snell's Law
Fermat's Principle
Law of Reflection (Correct answer)
Prentice's Rule

Correct answer: Law of Reflection

The Law of Reflection states that when light hits a surface, the angle of incidence equals the angle of reflection measured from the normal.

Question 145: When transposing a prescription from minus to plus cylinder form, the new sphere power will always be:

The same as the original sphere
Equal to the original cylinder power
More minus (or less plus) than the original sphere (Correct answer)
More plus than the original sphere

Correct answer: More minus (or less plus) than the original sphere

The new sphere is calculated by algebraically adding the original sphere and cylinder. Since you are starting with a minus cylinder, you will be adding a negative number to the sphere, which will always result in a new sphere power that is more minus (or less plus) than the original.

Question 146: Which term describes the ability of a lens material to polarize light at a specific angle, known as Brewster's angle?

Polarization by reflection (Correct answer)
Birefringence
Total internal reflection
Anti-reflection

Correct answer: Polarization by reflection

At Brewster's angle, reflected light becomes completely polarized parallel to the surface, which is the basis for polarized ophthalmic lenses reducing glare.

Question 147: According to FDA regulations, what is the purpose of the "drop ball test" for spectacle lenses?

To test the durability of the anti-scratch coating.
To ensure a minimum level of impact resistance. (Correct answer)
To verify the accuracy of the lens prescription.
To measure the optical clarity and Abbe value.

Correct answer: To ensure a minimum level of impact resistance.

The FDA requires that eyeglass and sunglass lenses sold in the U.S. meet a minimum standard for impact resistance to protect the wearer's eyes. The drop ball test, which involves dropping a 5/8-inch steel ball from a height of 50 inches onto the lens, is the standard method to verify this resistance. To pass, the lens must not fracture, chip, or crack.

Question 148: Which bifocal style produces zero image jump?

Flat-top (D-segment) bifocal
Round-segment bifocal
Ultex (curved-top) bifocal
Executive (Franklin split) bifocal (Correct answer)

Correct answer: Executive (Franklin split) bifocal

In an executive (E-style or Franklin split) bifocal, the segment's optical center is located precisely at the dividing line — the top of the segment. Because the distance from the segment top to its OC is zero, Prentice's Rule yields zero prism at the boundary, eliminating image jump entirely.

Question 149: Which condition is characterized by elevated intraocular pressure damaging the optic nerve?

Glaucoma (Correct answer)
Keratoconus
Macular degeneration
Uveitis

Correct answer: Glaucoma

Glaucoma is a group of conditions where optic nerve damage, often from elevated IOP, causes progressive vision loss.

Question 150: The choroid's primary function is to:

Drain aqueous humor
Control pupil size
Produce vitreous humor
Supply oxygen and nutrients to the outer retina (Correct answer)

Correct answer: Supply oxygen and nutrients to the outer retina

The highly vascular choroid supplies oxygen and nutrients to the outer retinal layers, including the photoreceptors.

Question 151: Which lens coating is applied primarily to repel water, smudges, and fingerprints from the lens surface?

Hard coat
UV absorbing coating
Hydrophobic/oleophobic coating (Correct answer)
Anti-reflective coating

Correct answer: Hydrophobic/oleophobic coating

Hydrophobic coatings repel water while oleophobic coatings repel oils; applied as the outermost layer on AR-coated lenses, they resist smudges, fingerprints, and water spots.

Question 152: What is the purpose of an 'aspheric' lens design in ophthalmic optics?

To reduce peripheral aberrations and allow a flatter, thinner lens (Correct answer)
To add UV protection without coatings
To eliminate the need for anti-reflective treatment
To increase lens thickness for durability

Correct answer: To reduce peripheral aberrations and allow a flatter, thinner lens

Aspheric surfaces vary in curvature from center to periphery, reducing oblique aberrations and enabling flatter, more cosmetically appealing lenses.

Question 153: For a bifocal lens, ANSI Z80.1 specifies the vertical prism imbalance between the two segment optical centers should not exceed:

0.50Δ (Correct answer)
0.25Δ
0.75Δ
0.33Δ

Correct answer: 0.50Δ

ANSI Z80.1 allows up to 0.50Δ of vertical prism imbalance between the two segments of a bifocal lens.

Question 154: In a progressive addition lens, where is the distance optical power measured?

At the prism reference point (PRP)
At the segment top
In the fitting cross or distance reference point (DRP) (Correct answer)
At the geometric center of the lens blank

Correct answer: In the fitting cross or distance reference point (DRP)

The distance power of a PAL is measured at the distance reference point (DRP) or fitting cross, which is positioned in front of the patient's pupil for distance viewing.

Question 155: Which layer of the cornea is responsible for maintaining its dehydrated, transparent state?

Descemet's membrane
Stroma
Bowman's layer
Endothelium (Correct answer)

Correct answer: Endothelium

The corneal endothelium actively pumps fluid out of the stroma via ion transport to maintain corneal transparency.

Question 156: A dispensary must retain patient prescription and sales records. The minimum record retention period is most commonly governed by:

State optician licensing board or state law (Correct answer)
Federal FDA regulations exclusively
ANSI Z80.1 requirements
ABO certification standards

Correct answer: State optician licensing board or state law

Record retention requirements for optical dispensaries are primarily set by individual state licensing boards or state statutes, and vary by state.

Question 157: An optician dispenses lenses with a power significantly different from the written prescription without the prescriber's approval. This action could constitute:

Acceptable clinical judgment
Standard optician discretion
Scope of practice violation or unauthorized practice (Correct answer)
A HIPAA violation only

Correct answer: Scope of practice violation or unauthorized practice

Dispensing lenses with powers materially different from the prescription without authorization exceeds an optician's scope of practice and may constitute unauthorized practice of optometry.

Question 158: When verifying a finished pair of spectacles, the lensometer is used to check all of the following EXCEPT:

The frame's pantoscopic tilt angle (Correct answer)
Cylinder power and axis of each lens
Sphere power of each lens
Optical center placement and prism

Correct answer: The frame's pantoscopic tilt angle

Pantoscopic tilt is a physical frame adjustment measured with a protractor or by visual assessment, not by the lensometer.

Question 159: What is 'base curve' in ophthalmic lens terminology?

The front surface curve of the lens, which determines the lens form (Correct answer)
The curvature of the frame front
The curve used to measure the patient's corneal curvature
The curve of the back surface that provides the prescription power

Correct answer: The front surface curve of the lens, which determines the lens form

Base curve refers to the front (convex) surface curvature of an ophthalmic lens; it determines the lens form (flat, steep, or best form) and affects peripheral optics.

Question 160: When dispensing lenses with anti-reflective (AR) coating, why must a hard coat be applied beneath the AR coating?

To increase the refractive index of the lens
To provide a smooth, durable surface for the AR layers to adhere to (Correct answer)
To block UV radiation from reaching the AR layers
To reduce the weight of the finished lens

Correct answer: To provide a smooth, durable surface for the AR layers to adhere to

Hard coat creates a smooth, durable surface that allows the thin vacuum-deposited AR layers to adhere properly and reduces microabrasions that would compromise coating performance.

Question 161: When light travels from a medium of lower index to a medium of higher index, it bends:

At the critical angle
Parallel to the surface
Toward the normal (Correct answer)
Away from the normal

Correct answer: Toward the normal

Light bends toward the normal when entering a denser (higher index) medium, as described by Snell's Law.

Question 162: The ABO recommends that opticians maintain their ABO certification through recertification every:

3 years (Correct answer)
1 year
2 years
5 years

Correct answer: 3 years

ABO-certified opticians must recertify every three years through continuing education or by retaking the examination.

Question 163: A patient's prescription reads +2.50 -1.25 x 090. What is the sphere power of the lens?

-1.25 D
+1.25 D
+3.75 D
+2.50 D (Correct answer)

Correct answer: +2.50 D

The sphere power is the first number in the prescription notation, which is +2.50 D.

Question 164: If a lens has a back vertex power of +3.00 D and a front vertex power of +2.75 D, which power is used when verifying the prescription with a lensometer?

Front vertex power
The average of both
Either power can be used
Back vertex power (Correct answer)

Correct answer: Back vertex power

The back vertex power is the standard used for lensometer verification because it represents the effective power at the back surface closest to the eye.

Question 165: An image formed by a concave (minus) lens is always:

Virtual and inverted
Virtual and erect (Correct answer)
Real and inverted
Real and erect

Correct answer: Virtual and erect

A concave (diverging) lens always forms a virtual, erect, and diminished image on the same side as the object.

Question 166: A patient returns two days after receiving new progressive addition lenses (PALs) and reports that the floor appears to 'swim' or warp when walking. What is the most likely cause?

The optical centers are set too high, inducing vertical prism
The add power is too high for the patient's age
The lens material has excessive chromatic aberration
The patient is viewing through the peripheral distortion zones inherent to progressive lens design (Correct answer)

Correct answer: The patient is viewing through the peripheral distortion zones inherent to progressive lens design

Progressive lenses have unavoidable peripheral blur/distortion zones on either side of the progressive corridor. When walking, patients who scan through these zones perceive spatial distortion (the 'swim' effect). Counseling the patient to turn their head rather than just their eyes, and allowing 1–2 weeks for neuroadaptation, resolves the complaint in most cases.

Question 167: Which aberration is responsible for the 'swim' or 'rocking' sensation some patients experience when adapting to new progressive addition lenses?

Longitudinal chromatic aberration
Field curvature
Distortion from the progressive lens design (Correct answer)
Spherical aberration

Correct answer: Distortion from the progressive lens design

Progressive lenses have unwanted astigmatism and distortion in the peripheral zones, which causes the swim or rocking perception until neuroadaptation occurs.

Question 168: The FDA classifies contact lenses as which type of medical device?

Class II or Class III medical devices regulated under 21 CFR 886 (Correct answer)
Over-the-counter devices requiring no regulation
Class I devices exempt from premarket notification
Prescription drugs regulated under the Food, Drug, and Cosmetic Act's drug provisions

Correct answer: Class II or Class III medical devices regulated under 21 CFR 886

Contact lenses are classified as Class II (daily wear soft) or Class III (extended wear) medical devices regulated by FDA under 21 CFR 886 (ophthalmic devices).

Question 169: In the context of Seidel aberrations, which two aberrations are most clinically significant for spectacle lens wearers?

Spherical aberration and coma
Oblique astigmatism and distortion (Correct answer)
Coma and field curvature
Distortion and chromatic aberration

Correct answer: Oblique astigmatism and distortion

Oblique astigmatism and distortion are the two most visually disruptive Seidel aberrations in spectacle lenses, particularly at high prescriptions.

Question 170: Which instrument is used to measure the vertex distance between the back surface of a spectacle lens and the front of the cornea?

Lensometer
Corneal topographer
Distometer (vertex distance gauge) (Correct answer)
Pupillometer

Correct answer: Distometer (vertex distance gauge)

A distometer (vertex distance gauge) measures the distance from the posterior lens surface to the anterior cornea, important for high-power prescriptions.

Question 171: When two thin lenses are placed in contact with each other, the combined power is:

The algebraic sum of their individual powers (Correct answer)
Always less than either individual power
Determined by the separation distance only
The product of their individual powers

Correct answer: The algebraic sum of their individual powers

For thin lenses in contact (zero separation), the combined power equals the algebraic sum: F_total = F1 + F2.

Question 172: When measuring a plano lens on a lensometer, the target should be:

Displaced from center and blurred
Centered and clear when the drum is at zero (Correct answer)
Completely invisible
Centered only when the drum is at +1.00

Correct answer: Centered and clear when the drum is at zero

A plano (no power) lens does not alter the light path, so the target remains centered and clear when the power drum is set to zero.

Question 173: A patient reports their anti-reflective coated lenses show a persistent colored sheen even after cleaning. This most likely indicates:

Normal thin-film interference from the AR coating
Excessive UV absorption
A delaminating or deteriorating AR coating (Correct answer)
Incorrect lens material for the coating

Correct answer: A delaminating or deteriorating AR coating

A persistent or irregular colored sheen after cleaning suggests the AR coating is delaminating or degrading and the lenses should be replaced.

Question 174: Minus lenses are thicker at the:

Edge (periphery) (Correct answer)
Optical center when decentered
Top edge only
Center

Correct answer: Edge (periphery)

Minus (concave) lenses are thinnest at the center and increase in thickness toward the edges.

Question 175: A patient's monocular PDs are 32 mm OD and 31 mm OS. The frame has an A measurement of 52 mm and a DBL of 18 mm. What is the decentration (in mm) required per eye?

OD: 0 mm, OS: 0 mm — no decentration needed
OD: 4 mm in, OS: 5 mm in
OD: 3 mm in, OS: 4 mm in (Correct answer)
OD: 1 mm out, OS: 2 mm out

Correct answer: OD: 3 mm in, OS: 4 mm in

The boxing center per eye sits at (A/2) + (DBL/2) = 26 + 9 = 35 mm from the frame midline. Decentration OD = 35 − 32 = 3 mm in (nasally). Decentration OS = 35 − 31 = 4 mm in. The OC must be moved nasally to align with the pupil because the frame's GC is wider than the patient's PD.

Question 176: When neutralizing a lens on a manual lensometer, you first focus the thin, single mires at +2.00 D with the axis wheel at 090. You then turn the power drum further into the plus to focus the thick, triple mires, which become clear at +3.50 D. What is the correct prescription in plus cylinder form?

+2.00 -1.50 x 090
+2.00 +1.50 x 090 (Correct answer)
+3.50 +1.50 x 180
+3.50 -1.50 x 180

Correct answer: +2.00 +1.50 x 090

In plus cylinder lensometry, the sphere power is the first reading where the single (sphere) lines are in focus (+2.00 D). The cylinder power is the difference between the second reading (triple lines) and the first reading (+3.50 - +2.00 = +1.50 D). The axis is the setting on the axis wheel when the sphere lines were focused (090).

Question 177: When verifying a plano lens on a lensometer, the mires should appear:

Rotated to the 90° axis
Split and unfocused regardless of the wheel setting
With a strong spherical shift requiring correction
Clear and focused at zero power with no cylinder (Correct answer)

Correct answer: Clear and focused at zero power with no cylinder

A plano lens has no refractive power, so the lensometer mires should focus clearly at zero on the power drum with no cylinder present.

Question 178: Which type of lens coating should be applied LAST during the coating process?

Hard coat
Anti-reflective coat (Correct answer)
Mirror coat
UV coat

Correct answer: Anti-reflective coat

The anti-reflective coating is applied as the final top coat because it must be deposited over all other coatings to function correctly.

Question 179: Which lens form produces the least oblique astigmatic error for a given prescription?

Corrected curve (best form) (Correct answer)
Flat form (plano front)
Meniscus with steep back curve
Equiconvex form

Correct answer: Corrected curve (best form)

Best-form (corrected curve) lenses are designed with base curves that minimize oblique astigmatic error for each prescription power.

Question 180: When verifying a finished lens with a lensometer, the optical center is found when:

The mire target is centered in the reticle with no prism displacement (Correct answer)
The axis wheel is set to 180°
The drum reading equals zero diopters
The mire target is blurred and displaced vertically

Correct answer: The mire target is centered in the reticle with no prism displacement

The optical center (OC) is located at the point on the lens where the mire is centered in the reticle (no prism displacement), regardless of power reading.

Question 181: Which of the following lens designs provides a continuous, seamless progression of power from distance to near vision without any visible lines?

Round-segment trifocal
Executive bifocal
Progressive addition lens (Correct answer)
Flat-top 28 bifocal

Correct answer: Progressive addition lens

A progressive addition lens (PAL) is a multifocal lens that corrects for presbyopia by gradually and smoothly changing in power from the top (for distance vision) to the bottom (for near vision). This design allows for clear vision at all distances without the visible lines characteristic of bifocals or trifocals.

Question 182: Induced prism resulting from a patient looking through a point other than the optical center is calculated using:

Fick's Principle
Prentice's Rule (Correct answer)
Snell's Law
Lensmaker's Equation

Correct answer: Prentice's Rule

Prentice's Rule states that prism (in prism diopters) = decentration (cm) × lens power (diopters), and is the standard formula for calculating induced prism.

Question 183: What is the approximate axial length of the average adult human eye?

24 mm (Correct answer)
20 mm
18 mm
28 mm

Correct answer: 24 mm

The average adult eye has an axial length of approximately 24 mm from the anterior corneal surface to the retina.

Question 184: In states with opticianry licensure laws, practicing without a valid license typically results in:

Loss of ABO certification only
A civil penalty only
Criminal charges, fines, and/or injunctions (Correct answer)
A formal warning letter

Correct answer: Criminal charges, fines, and/or injunctions

Unlicensed practice of opticianry in a state with licensure laws can result in criminal misdemeanor or felony charges, civil fines, and court injunctions.

Question 185: What sort of lens has a surface that is both convex and concave?

Plano-convex
Meniscus (Correct answer)
Biconvex
Biconcave

Correct answer: Meniscus

A meniscus lens is characterized by having one convex surface and one concave surface. This design allows for better optical performance, reduced peripheral aberrations, and a thinner, more aesthetically pleasing lens, especially for higher prescriptions. Most modern spectacle lenses are manufactured with a meniscus shape.

Question 186: Per ANSI Z80.1, what is the maximum allowable induced prism at the MRP for a single-vision lens with power greater than ±3.375 D?

1.50Δ
1.00Δ
0.33Δ
0.67Δ (Correct answer)

Correct answer: 0.67Δ

ANSI Z80.1 allows a maximum of 0.67Δ at the MRP for lenses stronger than ±3.375 D due to greater sensitivity to OC displacement.

Question 187: A high-minus lens patient complains of 'jack-in-the-box' phenomenon. What is happening?

Prism causes vertical diplopia at the edges
Objects suddenly appear when entering the peripheral field due to the ring scotoma (Correct answer)
The lens causes objects to jump when moving the eyes
Objects appear magnified in the center of the visual field

Correct answer: Objects suddenly appear when entering the peripheral field due to the ring scotoma

High-minus lenses create a ring scotoma at the prismatic lens edge, causing objects to 'pop' into view suddenly as they cross this boundary.

Question 188: Which ANSI standard specifically addresses the performance requirements for occupational and educational personal eye and face protection?

ANSI Z80.1
ANSI Z80.5
ANSI Z87.1 (Correct answer)
ANSI Z80.3

Correct answer: ANSI Z87.1

ANSI Z87.1 covers performance requirements for occupational and educational eye and face protection devices.

Question 189: A presbyopic patient has a +2.00 D near add with the segment center 4 mm below the distance OC. Assuming zero distance power, how much vertical prism acts at the segment center?

0.40Δ base up
0.80Δ base down (Correct answer)
0.80Δ base up
2.00Δ base down

Correct answer: 0.80Δ base down

Δ = 2.00 × 0.4 = 0.80Δ; looking below the add's OC with a plus add produces base-down prism.

Question 190: When measuring pupillary distance (PD) for a patient with significant facial asymmetry, which method is most accurate?

Distance PD minus 3mm for near
Binocular PD only
Monocular PD from each eye to the nose bridge (Correct answer)
Average of three binocular measurements

Correct answer: Monocular PD from each eye to the nose bridge

Monocular PD measurements account for facial asymmetry by measuring each eye independently from the nose bridge.

Question 191: Which ANSI standard specifically addresses the requirements for prescription ophthalmic lenses?

ANSI Z87.1
ANSI Z80.5
ANSI Z80.1 (Correct answer)
ANSI Z80.3

Correct answer: ANSI Z80.1

ANSI Z80.1 covers the requirements and tolerances for prescription ophthalmic lenses dispensed in the United States.

Question 192: Which frame material is most commonly associated with nickel allergy reactions in patients?

Beta titanium
Titanium
Aluminum
Monel (Correct answer)

Correct answer: Monel

Monel, a nickel-copper alloy widely used in eyewear frames, is the most common source of nickel contact dermatitis in optical patients.

Question 193: Which statement best describes how a polarized lens reduces glare?

It darkens automatically when exposed to bright light
It applies multiple thin layers to eliminate surface reflections
It has a gradient tint that is darker at the top than the bottom
It filters out light waves vibrating in the horizontal plane to reduce reflected glare (Correct answer)

Correct answer: It filters out light waves vibrating in the horizontal plane to reduce reflected glare

Polarized lenses contain a chemical film oriented to block horizontally polarized light, which is the primary component of glare reflected from flat surfaces like water, roads, and snow.

Question 194: When a patient's interpupillary distance is SMALLER than the frame's geometric center distance, the optical centers must be decentered in which direction?

No decentration is required because the power compensates automatically
Temporally (outward), to follow the pupils
Superiorly, to reduce induced vertical prism
Nasally (inward), to align with the pupils (Correct answer)

Correct answer: Nasally (inward), to align with the pupils

If the patient's PD is smaller than the frame GCD, the pupils are closer together than the boxing centers. The optical centers must be shifted nasally (inward) to coincide with the pupils. This inward decentration also induces base-in prism, which the optician must account for per Prentice's Rule.

Question 195: When a patient looks 30 degrees to the right through their spectacle lens, the effective power they experience differs from the labeled prescription due to:

Differences in coating reflectance
Changes in the lens material's refractive index
Off-axis aberrations, primarily oblique astigmatism (Correct answer)
Changes in the pupil size

Correct answer: Off-axis aberrations, primarily oblique astigmatism

Off-axis gaze subjects rays to oblique incidence, introducing oblique astigmatism that changes the effective power experienced by the wearer.

Question 196: Which muscle is responsible for constricting the pupil in bright light?

Orbicularis oculi
Sphincter pupillae (Correct answer)
Dilator pupillae
Superior rectus

Correct answer: Sphincter pupillae

The sphincter pupillae is a circular smooth muscle innervated by the parasympathetic nervous system that constricts the pupil.

Question 197: What is the vertex distance and why does it matter for prescriptions over ±4.00 D?

The distance from the back lens surface to the cornea; it affects effective lens power at the eye (Correct answer)
The distance from the frame front to the temples; it affects frame fit
The distance from the optical center to the pupil; it determines PD accuracy
The distance from the top of the frame to the pupil center; it determines seg height

Correct answer: The distance from the back lens surface to the cornea; it affects effective lens power at the eye

Vertex distance is the distance from the back surface of the lens to the cornea. For powers over ±4.00 D, this distance significantly affects the effective power at the eye.

Question 198: Prentice's Rule states that prism power (Δ) equals lens power (D) multiplied by which factor?

The decentration in centimeters (Correct answer)
The base curve in diopters
The lens thickness in mm
The vertex distance in mm

Correct answer: The decentration in centimeters

Prentice's Rule: Δ = D × c, where c is the decentration in centimeters.

Question 199: A patient wearing +3.50 D reading glasses holds their reading material 4 cm to the right of center. How much prism is induced horizontally?

0.875Δ Base Out
0Δ (Correct answer)
1.4Δ Base Out
14.0Δ Base Out

Correct answer: 0Δ

This question is a distractor. Prentice's rule applies when the *eye* moves away from the optical center, not when the object being viewed moves. As long as the patient looks straight through the optical center of the lens, no prism is induced, regardless of where the object is.

Question 200: To correct a frame that sits too low on the patient's face, the optician should:

Flatten the frame front
Extend the temple length
Raise the nose pads by angling the pad arms downward (Correct answer)
Increase the pantoscopic tilt

Correct answer: Raise the nose pads by angling the pad arms downward

Angling the pad arms downward moves the nose pads lower on the nose, raising the frame's overall position on the face.

Question 201: The optic chiasm is the anatomical site where which event occurs?

Nasal retinal fibers cross to the opposite side (Correct answer)
All optic nerve fibers cross to the opposite side
Visual signals convert from rod to cone pathways
Temporal retinal fibers cross to the opposite side

Correct answer: Nasal retinal fibers cross to the opposite side

At the optic chiasm, only the nasal retinal fibers (carrying temporal visual field information) decussate to the contralateral side.

Question 202: What is the ANSI Z80.1 tolerance for cylinder axis when the cylinder power is between 0.75 D and 1.50 D?

±5 degrees
±2 degrees
±7 degrees
±3 degrees (Correct answer)

Correct answer: ±3 degrees

ANSI Z80.1 specifies ±3 degrees of axis tolerance when the cylinder power falls between 0.75 D and 1.50 D.

ABO NOCE Basic Opticianry Exam

The ABO NOCE Basic Opticianry Exam exam validates essential knowledge and skills required for certification or licensure in this field.

200

Questions

150 min

Time Limit

70%

To Pass

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Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

abo-ncle.org — Test delivery, eligibility, fees, late registration, time limit, renewal, exam format, passing score, score release · verified Oct 2026