Aberrations of the Retinoscopic Reflex
With irregular astigmatism, almost any type of aberration may appear in the reflex. Spherical aberrations tend to increase the brightness at the center or periphery of the pupil, depending on whether they are positive or negative.
As neutrality is approached, 1 part of the reflex may be myopic, whereas the other may be hyperopic relative to the position of the retinoscope. This situation produces a scissors reflex. Causes of the scissors reflex include keratoconus, irregular corneal astigmatism, corneal or lenticular opacities, and spherical aberration.
All of these aberrant reflexes, in particular spherical aberration, are more noticeable in patients with large scotopic pupils. When a large pupil is observed during retinoscopy, the examiner should focus on neutralizing the central portion of the light reflex.
Table 4-1 provides a summary of the technique of retinoscopy using a plus cylinder phoropter.
Corboy JM. The Retinoscopy Book: An Introductory Manual for Eye Care Professionals. 5th ed. Thorofare, NJ: Slack; 2003.
Wirtschafter JD, Schwartz GS. Retinoscopy. In: Tasman W, Jaeger EA, eds. Duane’s Clinical Ophthalmology [CD-ROM]. Vol 1. Philadelphia: Lippincott Williams & Wilkins; 2006.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.