COT Ophthalmic Imaging and Photography 2 — Questions and Answers
Question 1: Which imaging modality uses infrared light to image the choroid below the retinal pigment epithelium?
- Fluorescein angiography
- Indocyanine green angiography (Correct answer)
- Optical coherence tomography
- Fundus autofluorescence
Correct answer: Indocyanine green angiography
Indocyanine green (ICG) angiography uses infrared wavelengths that penetrate the RPE, making it ideal for imaging choroidal vasculature.
Question 2: On optical coherence tomography, a hyporeflective (dark) space beneath the neurosensory retina is most consistent with:
- Epiretinal membrane
- Subretinal fluid (Correct answer)
- Drusen
- Intraretinal cysts
Correct answer: Subretinal fluid
Subretinal fluid appears as a hyporeflective (optically empty) space between the neurosensory retina and the RPE on OCT.
Question 3: A patient with nystagmus is scheduled for fundus photography. Which technique best compensates for uncontrolled eye movement?
- Increase flash intensity
- Use a shorter flash duration (Correct answer)
- Dilate the pupil more widely
- Switch to red-free filter
Correct answer: Use a shorter flash duration
A shorter flash duration (high-speed flash) freezes eye movement and reduces motion blur in patients with nystagmus.
Question 4: The safe maximum laser power for scanning laser ophthalmoscopy imaging is governed primarily by:
- ANSI Z80.36 laser safety standards (Correct answer)
- FDA 510(k) clearance only
- The manufacturer's warranty terms
- State optometry board regulations
Correct answer: ANSI Z80.36 laser safety standards
ANSI Z80.36 establishes the safety standards for ophthalmic instruments including laser exposure limits for SLO devices.
Question 5: In wide-field retinal imaging (e.g., Optos), the peripheral retina is captured using which optical principle?
- Direct ophthalmoscopy
- Ellipsoidal mirror scanning (Correct answer)
- Slit-lamp biomicroscopy
- Confocal aperture imaging
Correct answer: Ellipsoidal mirror scanning
Wide-field systems like Optos use an ellipsoidal mirror to redirect the scanning laser beam across up to 200° of the retina.
Question 6: Which artifact in OCT imaging appears as a bright vertical line caused by a highly reflective surface on the lens or cornea?
- Mirror artifact
- Blink artifact
- Specular reflection artifact (Correct answer)
- Defocus artifact
Correct answer: Specular reflection artifact
Specular reflection artifacts appear as bright vertical streaks when highly reflective surfaces (e.g., IOL, cornea) saturate the detector.
Question 7: During fluorescein angiography, the venous phase typically begins approximately how many seconds after dye injection?
- 5–8 seconds
- 10–15 seconds (Correct answer)
- 25–30 seconds
- 60–90 seconds
Correct answer: 10–15 seconds
The venous phase of fluorescein angiography typically begins 10–15 seconds after antecubital injection in a healthy patient.
COT Ophthalmic Imaging and Photography 2
Which imaging modality uses infrared light to image the choroid below the retinal pigment epithelium?