Changes of Visual Functions in Myopes Twelve Months after PhotorefractiveKeratectomy

Overview

1. 110 myopes undergoiyng photorefractive keratectomy (PRK) with refractionfrom - 0,25 D to -12,0 D were divided into 4 groups: A: upto -2.75 D, B: -3.0 D to -5.75D, C: -6.0 D to -8,75 D and D: -9.0 D to -12,0 D. BCVA using the computerized methodwith Landolt rings and CS using an adjustment method with ascendent anddescendent approach to treshold contrast adaptation on a computerized systemof the Contrast sensitivity 8010 type were examined in patients before and 1 yearafter PRK. 20 emmetropes of the same median age were evaluated as a controlgroup.2. Preoperative BCVA and CS in myopes of all four groups was significantly lower(p < 0,05 až p < 0,001), compared to controls. Decrease of functions was proportionalto refraction.3. With increasing refraction less patients were within ±0,5 D and ±1,0 D aftersurgery.4. Twelve months after PRK, BCVA in the group A reached the level of controls,CS in the same time interval was equal to control even in groups A and B.5. According to results of our study, PRK is a suitable method for myopia upto-6.0 D.

Key words:
photorefractive keratectomy, myopia, contrast sensitivity, logMARcharts.