COT Ophthalmic Imaging and Photography 4

Question 1

Enhanced depth imaging (EDI) OCT is specifically designed to improve visualization of which ocular structure?

Accepted Answer

Choroid

Answer

EDI-OCT inverts the sensitivity roll-off to place the zero-delay line deeper, improving signal from the choroid and sub-RPE layers.

Question 2

Which grading scale is most commonly used to standardize documentation of diabetic retinopathy severity from fundus photographs?

Accepted Answer

Early Treatment Diabetic Retinopathy Study (ETDRS) scale

Answer

The ETDRS severity scale, developed from the landmark clinical trial, provides a standardized 13-level grading system for diabetic retinopathy.

Question 3

In fluorescein angiography, 'window defect' hyperfluorescence is caused by:

Accepted Answer

Loss of RPE blocking pigment revealing background choroidal fluorescence

Answer

Window defects occur when RPE atrophy or thinning removes the normal blocking layer, allowing background choroidal fluorescence to shine through.

Question 4

A patient's OCT shows a 'double hump' or 'W-shape' reflectivity profile in the outer retina. This pattern is most associated with:

Accepted Answer

Normal foveal pit anatomy

Answer

The normal foveal OCT profile shows a central pit flanked by the thicker parafoveal retina, creating a characteristic 'W' or double-hump appearance.

Question 5

Which photographic technique is used to map the anterior segment angle and document angle-closure risk?

Accepted Answer

Scheimpflug imaging (Pentacam)

Answer

Scheimpflug-based cameras (e.g., Pentacam) capture cross-sectional images of the anterior segment and can measure anterior chamber depth and angle parameters.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT Ophthalmic Imaging and Photography 4