COT Ophthalmic Imaging and Photography 5

Question 1

A photographer notices the fundus image has a crescent-shaped dark shadow on one edge. The most likely cause is:

Accepted Answer

Patient's eyelid partially covering the pupil

Answer

A crescent-shaped shadow (eyelid artifact) occurs when the patient's upper or lower eyelid partially occludes the pupil during image capture.

Question 2

Stereo fundus photography achieves a three-dimensional view by:

Accepted Answer

Capturing two images from slightly different angles through the same pupil

Answer

Stereo fundus photography captures two sequential images with the camera decentered slightly left and right, simulating binocular parallax for 3D viewing.

Question 3

In OCT imaging, 'shadow artifact' beneath a retinal vessel is caused by:

Accepted Answer

Absorption and scattering of the OCT beam by blood blocking deeper signal

Answer

Blood in retinal vessels strongly absorbs and scatters the OCT beam, producing a dark (hyporeflective) shadow beneath the vessel in the scan.

Question 4

Which imaging modality is considered the gold standard for diagnosing choroidal neovascularization (CNV) location and activity in wet AMD?

Accepted Answer

Fluorescein angiography

Answer

Fluorescein angiography remains the gold standard for characterizing CNV type (classic vs. occult), boundaries, and activity to guide anti-VEGF treatment decisions.

Question 5

The Specular microscope measures which property of the corneal endothelium?

Accepted Answer

Endothelial cell density and morphology

Answer

Specular microscopy analyzes the reflected image of the endothelial cell mosaic to measure cell density (cells/mm²), cell size variation (CV), and hexagonality.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT Ophthalmic Imaging and Photography 5