Surgical Results of Photorefractive Keratectomy Using Different Operative Modes

Summary

Purpose: To compare the predictability, efficacy, and safety of photorefractive keratectomy (PRK) by using differen excimer laser treatment modes.

Setting: National Taiwan University Hospital, Taipei, Taiwan.Methods: We studied 153 eyes of 99 patients that underwent PRK for myopia, for a follow-up period of at least 6 months. All patients were sequentially assigned to received one of the three following surgical modes: mode 1: PRK using the Summit OmniMed excimer laser, mode 2: PRK with the Summit ApexPlus laser, and mode 3: PRK with the Summit ApexPlus machine with anticentral island pretreatment. Results: The homogenous topographic pattern 6 months after treatment was 76% in mode 1, 70% in mode 2 and 88% in mode 3. In the low myopia (≤−6.0 D) group, the residual refractive error was −0.79 ± 0.59 D in mode l, −0.94 ± 1.02 D in mode 2, and −0.3l ± 0.42 D in mode 3. In the high myopia group (> −6.0 D), the residual refractive error was −1.93 ± l.51 D in mode 1, −1,54 ± 0.88 D in mode 2, and −0.70 ± O.8l D in mode 3 Uncorrected visual acuity of 20/40 or better, was achieved in 100% in mode 1, 73% in mode 2 and 100%in mode 3 in the low myopia group, and 92% in mode l, 83% in mode 2 and 94% in mode 3 in the high myopia group.

Conclusions: PRK appears to be a predictable and effective procedure to correct myopia. The OmniMed excimer laser achieved better surgical results than did the ApexPlus laser. An anticentral-island pretreatment program effectively improves the surgical results of the ApexPlus laser.