In retinoscopy, which of the following conditions would produce a 'with movement' of the retinoscopy reflex when using a plane mirror at a working distance of 67 cm?

• A Hypermetropia of +3.00D ✓
• B Myopia of -2.00D
• C Emmetropia
• D Myopia of -3.00D

Explanation

With a plane (flat) mirror retinoscope at 67 cm working distance, the far point of the examiner is at 1.5D. An eye that needs less than 1.5D of minus correction (i.e., less myopic than -1.5D, or hypermetropic) shows 'with movement.' A hypermetrope of +3.00D shows 'with movement' because the parallel rays diverge on exiting the hypermetropic eye. The neutralizing lens for this eye would be approximately +3.00 + 1.50 (working distance) = +4.50D. Understanding the optics underpinning retinoscopy motion direction is a key examination concept.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.