EXCIMER-LASER PHOTOREFRACTIVE KERATECTOMY FOR MYOPIA

To evaluate the safety, effectiveness and stability of excimer laser p hotorefractive keratectomy (PRK) treatment, we studied its posttreatme nt results in 44 normal-sighted myopic eyes where a 193-nm emission wa velength excimer laser was used to correct myopia. The eyes were divid ed into three groups according to the preoperative refractive error an d attempted correction: group I, preoperative myopia less than or equa l to 6.00 diopters (D), full correction; group II, preoperative myopia between 6.00 and 8.00 D, full correction; group III, preoperative myo pia > 8.00 D, attempted correction of 8.00 D. Percentages of relative spherical equivalents (ie, observed spherical equivalent - expected sp herical equivalent) within +/- 1.0 D 3 months after treatment were 95% in group I, 64% in group II and 67% in group III. Uncorrected visual acuity of 20/40, or better, was achieved in 100% of eyes in group I, a nd 92% in group II at 6 months. Initial overcorrection followed by myo pic regression was observed in all groups. The refractive outcome in o ur study was stable 3 months after surgery. Anterior stromal haze Tvas mild and disappeared gradually 3 months postoperatively. The greater the diopter correction needed, the higher the grade of corneal haze (p < 0.01). There were no significant complications. The results of this study demonstrated that excimer laser PRE; appears to be a reasonably predictable and stable procedure to correct low to moderate myopia.