COT - Certified Ophthalmic Technician Ophthalmic Imaging and Photography Questions and Answers

Question 1

A patient undergoing fluorescein angiography begins to show dye filling the retinal arterioles approximately one to two seconds after the choroidal flush. Which phase of the angiogram is occurring?

Accepted Answer

Arterial Phase

Answer

The arterial phase of a fluorescein angiogram is characterized by the filling of the retinal arterioles, which typically happens 1-2 seconds after the initial choroidal flush. The choroidal phase is the very first appearance of the dye in the choroid. The venous phase follows the arterial phase, showing the veins filling. The late phase occurs several minutes later as the dye is eliminated.

Question 2

When performing fundus photography on a patient with small pupils, a bright, orange-colored crescent appears at the edge of the image. What is the most likely cause of this artifact?

Accepted Answer

Illumination beam reflecting off the iris

Answer

An orange or bright crescent at the margin of a fundus photograph is a common artifact caused by the camera's illumination light hitting and reflecting off the edge of the iris, especially in cases of poor pupillary dilation. To correct this, the camera's joystick should be moved away from the crescent to better center the light beam through the pupil.

Question 3

A technician is reviewing a corneal topography map to assist in fitting a patient for rigid gas-permeable (RGP) contact lenses. The axial map displays a localized area with predominantly red and orange colors, surrounded by green. How should the technician interpret this finding?

Accepted Answer

A steep area of the cornea

Answer

On a standard axial corneal topography map, warmer colors like red and orange represent steeper areas of the cornea, while cooler colors like blue and green indicate flatter regions. This information is crucial for selecting the appropriate base curve for a contact lens.

Question 4

Which of the following imaging modalities provides a cross-sectional, high-resolution view of the retinal layers, making it invaluable for detecting and monitoring conditions like macular edema and vitreomacular traction?

Accepted Answer

Optical Coherence Tomography (OCT)

Answer

Optical Coherence Tomography (OCT) is a non-invasive imaging test that uses light waves to take cross-section pictures of the retina. It allows for the visualization of each of the retina’s distinct layers, which is essential for the diagnosis and management of retinal diseases like macular edema, macular holes, and epiretinal membranes.

Question 5

While acquiring an Optical Coherence Tomography (OCT) scan of the macula, the technician notes a low Signal Strength (SS) value and observes significant motion artifacts and poor delineation of the retinal layers. Which action is most appropriate to improve the scan quality?

Accepted Answer

Re-align the patient, coach them to fixate steadily, and re-scan.

Answer

Poor OCT image quality, indicated by low signal strength and artifacts, is often due to factors like poor patient alignment, blinking, or unsteady fixation. The best initial step is to reinstruct and realign the patient to ensure their eye is properly positioned and stable before recapturing the image. Scan quality is critical for accurate interpretation and diagnosis.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Ophthalmic Imaging and Photography Questions and Answers