Effect of radial keratotomy on the contrast sensitivity function

A group of six patients had the radial keratotomy (RK) procedure carried out on one eye only as part of the Prospective Evaluation of Radial Keratotomy (PERK) study. Contrast sensitivity was measured in the operated and unoperated eyes of these patients under conditions of maximum correction and no over-correction. Analysis of variance indicated a significant reduction in the contrast sensitivity function (CSF) of the operated eye postsurgically when compared to the operated eye for all patients. Analysis of results for individual patients indicated that three of the six patients showed significant reductions in CSF between the two eyes. Reasons for these changes are offered in terms of the change in glare produced by the surgical procedure and the difference in spherical aberration of the eye.