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Ophthalmic Imaging and Photography Flashcards

7 cards from real COT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

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  1. Fundus autofluorescence (FAF) imaging relies on the natural fluorescence of which substance in the retinal pigment epithelium?

    Answer: Lipofuscin

    Lipofuscin, a byproduct of incomplete photoreceptor outer segment digestion, accumulates in the RPE and is the primary source of fundus autofluorescence.

  2. When performing corneal topography, the Placido disc system measures corneal curvature by analyzing:

    Answer: Reflected concentric ring images from the corneal surface

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

  3. A cotton-wool spot on fundus photography corresponds pathologically to:

    Answer: Focal nerve fiber layer infarction

    Cotton-wool spots represent focal ischemic infarcts of the nerve fiber layer causing axoplasmic flow stasis and cytoid bodies.

  4. Which OCT scan pattern provides the most comprehensive macular thickness map for detecting early diabetic macular edema?

    Answer: Macular cube (raster) scan

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

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

    Answer: Corneal epithelial defects

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

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

    Answer: 50 μm posterior to the temporal disc margin

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

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

    Answer: Superior or inferior neuroretinal rim thinning

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