Refraction and Retinoscopy Flashcards

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?

Answer: +3.00 D

Latent hyperopia = cycloplegic refraction − manifest refraction = +4.50 − (+1.50) = +3.00 D.

In retinoscopy, what is the purpose of the sleeve adjustment on a streak retinoscope?

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.

When performing retinoscopy at 50 cm, what is the working distance lens value that must be subtracted?

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.

What technique is used to control accommodation during manifest refraction in young patients without cycloplegia?

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.

A patient's refraction is plano +2.00 ×045. This represents what type of astigmatism?

Answer: Simple hyperopic astigmatism

One meridian (plano) is emmetropic and the other (+2.00 D) is hyperopic, defining simple hyperopic astigmatism.

Which finding on retinoscopy would prompt you to use a plus lens to reach neutralization?

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.

What is the MPMVA endpoint in subjective refraction?

Answer: Maximum plus to maximum visual acuity

MPMVA stands for Maximum Plus to Maximum Visual Acuity, ensuring accommodation is fully relaxed at the endpoint.