COT Refraction and Retinoscopy 2 — Questions and Answers
Question 1: During retinoscopy, if the examiner works at 67 cm, what working distance lens should be subtracted from the gross retinoscopy finding?
- +1.00 D
- +1.50 D (Correct answer)
- +2.00 D
- +2.50 D
Correct answer: +1.50 D
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?
- −2.25 D (Correct answer)
- −3.75 D
- −1.50 D
- −2.75 D
Correct answer: −2.25 D
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?
- With motion
- Against motion
- Neutralization (no motion) (Correct answer)
- Scissors motion
Correct answer: Neutralization (no motion)
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:
- −3.00 +1.00 ×090 (Correct answer)
- −2.00 +1.00 ×090
- −3.00 +1.00 ×180
- −1.00 −1.00 ×090
Correct answer: −3.00 +1.00 ×090
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:
- Against motion, requiring minus lenses (Correct answer)
- With motion, requiring plus lenses
- Neutral, no correction needed
- Scissors motion due to irregular astigmatism
Correct answer: Against motion, requiring minus lenses
High myopes have their far point in front of the examiner, producing an against motion reflex that is neutralized with minus lenses.
Question 6: What does the term 'fogging' accomplish during subjective refraction?
- It relaxes accommodation by initially over-plusing the patient (Correct answer)
- It induces miosis to improve depth of focus
- It measures the true cylinder axis only
- It prevents the patient from reading the chart
Correct answer: It relaxes accommodation by initially over-plusing the patient
Fogging uses excess plus power to blur the patient's vision, relaxing accommodation so the starting point avoids over-minus.
Question 7: When performing retinoscopy on a patient with high astigmatism, a 'scissors' reflex is sometimes seen. What is the best approach?
- Use a cylindrical lens to neutralize each principal meridian separately (Correct answer)
- Add more working distance to widen the reflex
- Switch to a direct ophthalmoscope
- Dilate the pupil further before proceeding
Correct answer: Use a cylindrical lens to neutralize each principal meridian separately
Scissors motion indicates irregular astigmatism or high regular astigmatism; neutralize each meridian independently with cylinder correction.
COT Refraction and Retinoscopy 2
During retinoscopy, if the examiner works at 67 cm, what working distance lens should be subtracted from the gross retinoscopy finding?