JCAHPO Imaging 3 — Questions and Answers
Question 1: Indocyanine green angiography (ICGA) is preferred over fluorescein angiography for evaluating:
- Diabetic macular edema
- Choroidal vasculature and polypoidal choroidal vasculopathy (Correct answer)
- Retinal vein occlusion
- Optic nerve head drusen
Correct answer: Choroidal vasculature and polypoidal choroidal vasculopathy
ICG dye is lipophilic and protein-bound, allowing better penetration of the RPE to visualize choroidal circulation and polypoidal structures.
Question 2: On a Humphrey visual field test, a 'nerve fiber bundle defect' is characterized by:
- Central scotoma respecting the horizontal meridian
- Arcuate scotoma following the course of nerve fibers (Correct answer)
- Bitemporal hemianopia
- Altitudinal defect above or below fixation
Correct answer: Arcuate scotoma following the course of nerve fibers
Nerve fiber bundle defects follow the arcuate pattern of retinal nerve fibers as they course around the macula to the optic nerve.
Question 3: The purpose of the internal fixation target in a slit-lamp-based OCT is to:
- Illuminate the fundus for photography
- Stabilize the patient's gaze on the area of interest (Correct answer)
- Provide a reference for axial length measurement
- Calibrate the instrument's scale bar
Correct answer: Stabilize the patient's gaze on the area of interest
The internal fixation target helps the patient maintain stable gaze on the desired retinal location to ensure consistent and reproducible scans.
Question 4: What does RNFL thickness measured by OCT represent?
- The thickness of all retinal layers combined
- The thickness of the retinal nerve fiber layer containing ganglion cell axons (Correct answer)
- The distance from the ILM to the RPE
- The choroidal thickness beneath the retina
Correct answer: The thickness of the retinal nerve fiber layer containing ganglion cell axons
RNFL thickness on OCT measures the innermost retinal layer containing ganglion cell axons; thinning indicates glaucomatous or other optic nerve damage.
Question 5: A patient has a B-scan ultrasound showing high internal reflectivity within a choroidal lesion. This pattern is most consistent with:
- Choroidal melanoma
- Choroidal hemangioma (Correct answer)
- Choroidal metastasis
- Choroidal nevus
Correct answer: Choroidal hemangioma
Choroidal hemangiomas classically show high internal reflectivity on B-scan due to their vascular and fibrous structure, unlike melanomas which are typically low reflective.
Question 6: Which feature on fluorescein angiography distinguishes classic CNV from occult CNV?
- Classic CNV shows early well-defined hyperfluorescence with late leakage; occult is poorly defined (Correct answer)
- Classic CNV is seen only on ICGA; occult is seen on FA
- Classic CNV appears in the early transit phase only
- Occult CNV leaks earlier than classic CNV
Correct answer: Classic CNV shows early well-defined hyperfluorescence with late leakage; occult is poorly defined
Classic CNV has a well-demarcated lacy hyperfluorescent network early that leaks late, while occult CNV has poorly defined, stippled or fibrovascular pigment epithelial detachment patterns.
Question 7: In corneal confocal microscopy, which cell type is specifically imaged to assess corneal nerve health?
- Keratocytes
- Endothelial cells
- Sub-basal nerve plexus fibers (Correct answer)
- Bowman's layer fibrocytes
Correct answer: Sub-basal nerve plexus fibers
Confocal microscopy images the sub-basal nerve plexus in the corneal epithelium, and nerve fiber density/morphology is used to assess neuropathy.
JCAHPO Imaging 3
Indocyanine green angiography (ICGA) is preferred over fluorescein angiography for evaluating: