Optical aberrations of the eye following radial keratotomy

Abstract

The quality of the eye's in-focus optical image (and visual performance) is directly influenced by the magnitude of the eye's higher-order wave aberrations. Although there have been numerous studies of the normal eye, little is known about the optics of eyes after various clinical interventions (e.g., radial keratotomy, epikeratophakia, and corneal transplants). To help fill this information void, wave aberrations were measured with the Howland and Howland aberroscope on 15 radial-keratotomy (RK) patients and nine normal control subjects (no surgery) before and approximately 7, 120, 240, and 360 days after surgery. Although measurements could always be performed on the control subjects (88 of 88 times), RK patients' optics were usually sufficiently disrupted outside the surgery-free zone that quantification of the wave aberrations was impossible. In RK eyes where measurements were possible (12 of 96 times), the measured aberrations were, as a rule, larger than those of the control subjects and the optical consequences were more severe. These measurements are consistent with the frequent report from RK patients that their vision is excellent under high photopic conditions, where their pupil is small, but that it deteriorates under mesopic-to- scotopic conditions, where the pupil is relatively large.