VISUAL FUNCTION BEFORE AND AFTER PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA

BACKGROUND: To date, Snellen visual acuity and postoperative refractio n have been used to evaluate the results of photorefractive keratectom y. However, other parameters, such as contrast sensitivity function an d glare, may be affected by refractive surgery and lead to unsatisfact ory visual performance. This prospective study is aimed at evaluating the effect of photorefractive keratectomy on contrast sensitivity func tion and glare. SUBJECTS AND METHODS: Static contrast sensitivity func tion, dynamic contrast sensitivity function, and glare sensitivity wer e evaluated in 22 myopic eyes before as well as 1, 3, and 6 months aft er photorefractive keratectomy. The eyes tested were divided into thre e groups, according to the amount of myopia: group 1, from - 4.00 to - 8.00 diopters (D); group 11, from - 8.25 to - 11.00 D; group III, fro m - 11.25 to - 20.00 D. RESULTS: Both static and dynamic contrast sens itivity function at the intermediate spatial frequencies were altered at 1 month after photorefractive keratectomy, with a trend toward reco very at 3 and 6 months postoperatively. Glare sensitivity was not sign ificantly affected by surgery. CONCLUSIONS: Contrast sensitivity funct ion and glare testing may show abnormalities in the presence of optima l visual and refractive results. These tests may result especially imp ortant for the evaluation of new refractive surgical procedures.