COT Refraction and Retinoscopy 4 — Questions and Answers
Question 1: A patient has a cycloplegic refraction of +4.50 D and a manifest refraction of +1.50 D. What is the amount of latent hyperopia?
- +3.00 D (Correct answer)
- +6.00 D
- +3.50 D
- +2.50 D
Correct answer: +3.00 D
Latent hyperopia = cycloplegic refraction − manifest refraction = +4.50 − (+1.50) = +3.00 D.
Question 2: In retinoscopy, what is the purpose of the sleeve adjustment on a streak retinoscope?
- To change from a diverging (plane mirror) to a converging (concave mirror) beam (Correct answer)
- To rotate the streak 90°
- To change the color of the light source
- To adjust the pupil size of the reflected beam
Correct answer: To change from a diverging (plane mirror) to a converging (concave mirror) beam
Moving the sleeve up or down shifts between plane and concave mirror modes, affecting the direction of beam divergence.
Question 3: When performing retinoscopy at 50 cm, what is the working distance lens value that must be subtracted?
- +2.00 D (Correct answer)
- +1.50 D
- +1.00 D
- +2.50 D
Correct answer: +2.00 D
At 50 cm, vergence = 1/0.50 = +2.00 D, so +2.00 D must be subtracted from the gross finding to obtain the net refraction.
Question 4: What technique is used to control accommodation during manifest refraction in young patients without cycloplegia?
- Fogging with excess plus and asking the patient to read smallest legible letters (Correct answer)
- Patching one eye at a time
- Using a pinhole occluder
- Performing retinoscopy without any room light
Correct answer: Fogging with excess plus and asking the patient to read smallest legible letters
Fogging relaxes accommodation by making the optical system slightly hyperopic, preventing over-minusing during subjective refraction.
Question 5: A patient's refraction is plano +2.00 ×045. This represents what type of astigmatism?
- Simple hyperopic astigmatism (Correct answer)
- Simple myopic astigmatism
- Compound hyperopic astigmatism
- Mixed astigmatism
Correct answer: Simple hyperopic astigmatism
One meridian (plano) is emmetropic and the other (+2.00 D) is hyperopic, defining simple hyperopic astigmatism.
Question 6: Which finding on retinoscopy would prompt you to use a plus lens to reach neutralization?
- With motion reflex (Correct answer)
- Against motion reflex
- No motion (neutralization)
- Scissors reflex only
Correct answer: With motion reflex
With motion means the far point is behind the examiner, indicating hyperopia, and plus lenses move the far point forward to neutralize.
Question 7: What is the MPMVA endpoint in subjective refraction?
- Maximum plus to maximum visual acuity (Correct answer)
- Minimum plus to maximum visual acuity
- Maximum minus for the best acuity
- Minimum minus for the best acuity
Correct answer: Maximum plus to maximum visual acuity
MPMVA stands for Maximum Plus to Maximum Visual Acuity, ensuring accommodation is fully relaxed at the endpoint.
COT Refraction and Retinoscopy 4
A patient has a cycloplegic refraction of +4.50 D and a manifest refraction of +1.50 D.
What is the amount of latent hyperopia?