CPOA Diagnostic Testing 4 — Questions and Answers
Question 1: When performing non-contact tonometry (air-puff), the puff of air:
- Briefly flattens the cornea and the instrument measures the time or force required (Correct answer)
- Measures IOP indirectly by detecting scleral indentation
- Stains the tear film to assess fluid pressure
- Dilates the pupil to visualize the optic nerve
Correct answer: Briefly flattens the cornea and the instrument measures the time or force required
Non-contact tonometry directs a puff of air at the cornea, and the instrument measures the corneal applanation time or the reflected light to calculate IOP.
Question 2: A pupil that is larger than normal and does not constrict to light but constricts to accommodation is characteristic of:
- Adie's tonic pupil (Correct answer)
- Horner syndrome
- Third nerve palsy
- Afferent pupillary defect (APD)
Correct answer: Adie's tonic pupil
Adie's tonic pupil (Holmes-Adie syndrome) is a benign condition with a dilated, light-near dissociated pupil that constricts slowly and tonically to near targets.
Question 3: In OCT imaging of the macula, drusen appear as:
- Deposits causing focal elevation of the retinal pigment epithelium (Correct answer)
- Fluid-filled spaces within the neurosensory retina
- Hyperreflective lines beneath the inner plexiform layer
- Absent signal in the outer nuclear layer
Correct answer: Deposits causing focal elevation of the retinal pigment epithelium
Drusen appear on OCT as focal elevations or bumps of the retinal pigment epithelium (RPE), representing lipid and protein deposits associated with AMD.
Question 4: A technician is preparing a patient for fluorescein angiography. The most important question to ask before injecting fluorescein is:
- Does the patient have any allergies, especially to fluorescein or iodine? (Correct answer)
- Has the patient eaten within the past two hours?
- Can the patient sit still for 45 minutes?
- Does the patient wear contact lenses?
Correct answer: Does the patient have any allergies, especially to fluorescein or iodine?
Allergic reactions — including anaphylaxis — can occur with intravenous fluorescein, so allergy history must be confirmed before injection.
Question 5: The retinal nerve fiber layer (RNFL) is best evaluated using which imaging modality?
- Optical coherence tomography (OCT) (Correct answer)
- Fundus fluorescein angiography
- B-scan ultrasonography
- Corneal topography
Correct answer: Optical coherence tomography (OCT)
OCT provides high-resolution cross-sectional imaging of the RNFL thickness, making it the standard tool for detecting glaucomatous damage to the nerve fiber layer.
Question 6: A swinging flashlight test (RAPD test) is used to detect a defect in the:
- Afferent pupillary pathway (optic nerve or retina) (Correct answer)
- Efferent pupillary pathway (cranial nerve III)
- Ciliary body's accommodative response
- Corneal light reflex symmetry
Correct answer: Afferent pupillary pathway (optic nerve or retina)
The swinging flashlight test reveals a relative afferent pupillary defect (RAPD) by comparing the direct and consensual pupillary responses between eyes, indicating optic nerve or significant retinal disease.
Question 7: Specular microscopy of the cornea is used to evaluate:
- Corneal endothelial cell density and morphology (Correct answer)
- Corneal epithelial surface irregularity
- Anterior chamber angle width
- Tear film lipid layer thickness
Correct answer: Corneal endothelial cell density and morphology
Specular microscopy images the endothelial cell layer and measures cell density (cells/mm²) and morphology, which is important before cataract surgery or contact lens fitting.
CPOA Diagnostic Testing 4
When performing non-contact tonometry (air-puff), the puff of air: