COT Low Vision and Optical Aids

Question 1

Which statement best defines 'low vision' as used in clinical ophthalmic practice?

Accepted Answer

Visual acuity of 20/70 or worse in the better eye that cannot be corrected to normal with conventional lenses

Answer

Low vision is defined as best-corrected visual acuity of 20/70 or worse in the better eye that cannot be improved to normal with standard spectacle correction.

Question 2

What is the leading cause of low vision in adults over 65 years of age in the United States?

Accepted Answer

Age-related macular degeneration

Answer

Age-related macular degeneration (AMD) is the leading cause of low vision and legal blindness in Americans over age 65.

Question 3

Using the Kestenbaum rule, what reading add should be prescribed for a patient with a best-corrected distance acuity of 20/200?

Accepted Answer

+10.00 D

Answer

The Kestenbaum rule prescribes an add equal to the denominator divided by the numerator of the Snellen fraction: 200 ÷ 20 = +10.00 D.

Question 4

Which technique involves training a patient with a central scotoma to use a peripheral retinal area for fixation?

Accepted Answer

Eccentric viewing

Answer

Eccentric viewing is a rehabilitation technique that teaches patients to shift fixation to a preferred retinal locus (PRL) outside the damaged fovea.

Question 5

Which type of magnification is achieved simply by moving an object closer to the patient's eye, without using any optical device?

Accepted Answer

Relative distance magnification

Answer

Relative distance magnification results from decreasing the viewing distance, which enlarges the retinal image without requiring any optical device.

COT - Certified Ophthalmic Technician Practice Test

COT - Certified Ophthalmic Technician Practice Test

COT Low Vision and Optical Aids