COT Refraction and Retinoscopy 2

Question 1

During retinoscopy, if the examiner works at 67 cm, what working distance lens should be subtracted from the gross retinoscopy finding?

Accepted Answer

+1.50 D

Answer

At 67 cm working distance, the vergence of light from that distance equals +1.50 D, which must be subtracted from the gross finding.

Question 2

A patient's manifest refraction is −3.00 +1.50 ×090. What is the spherical equivalent?

Accepted Answer

−2.25 D

Answer

Spherical equivalent = sphere + (cylinder/2) = −3.00 + (1.50/2) = −3.00 + 0.75 = −2.25 D.

Question 3

Which retinoscopy reflex motion indicates that the eye is corrected and the far point coincides with the examiner's peephole?

Accepted Answer

Neutralization (no motion)

Answer

Neutralization occurs when no movement of the reflex is seen, meaning the far point is at the examiner's working distance.

Question 4

In plus-cylinder notation, a refraction of −2.00 −1.00 ×180 converted to minus-cylinder form is:

Accepted Answer

−3.00 +1.00 ×090

Answer

Transpose by adding cylinder to sphere (−2.00 + (−1.00) = −3.00), change cylinder sign (+1.00), and rotate axis 90° (090).

Question 5

A patient with high myopia shows a bright, fast retinoscopy reflex. This indicates the reflex is:

Accepted Answer

Against motion, requiring minus lenses

Answer

High myopes have their far point in front of the examiner, producing an against motion reflex that is neutralized with minus lenses.

COT - Certified Ophthalmic Technician Practice Test