Background: To report the 5 and 3 year results of photorefractive keratectomy for -1 to -6 D of myopia and less than 1.50 D astigmatism.
Methods: All eyes were treated with a VISX 20/20 excimer laser with an ablation diameter of 5 mm. Our initial series of 133 eyes were treated in four groups: IIA, IIB, III and III No Nitrogen and reported on previously with follow-up from 6 to 36 months. The present report extends the observation period to 3 and 5 years for 114 eyes.
Results: Groups IIA and IIB were followed for 5 years and Groups III and III No Nitrogen for 3 years. Group IIA achieved 77% (10 of 13 eyes) +/-1.00 D (54% within +/-0.50 D) of emmetropia with stability from 6 months and 54% (seven of 13 eyes) had visual acuity of 20/20 or better. In Group IIB, 35% (six of 17 eyes) were +/-1.00 D (18% within +/-0.50 D) of emmetropia and stable from 18 months. Two of 17 eyes (12%) had 20/20 or better visual acuity. Group III had 76% (42 of 55 eyes) within +/-1.00 D (51% within +/-0.50 D) of emmetropia with stability after 12 months; 60% (33 of 55 eyes) had 20/20 or better visual acuity. Group III No Nitrogen had 73% (11 of 15 eyes) within +/-1.00 D (60% within +/-0.50 D) of emmetropia and were stable after 6 months; 47% (seven of 15 eyes) had 20/20 or better visual acuity. There was no hyperopic refractive shift. No correlation was found between the percent of correction achieved and preoperative amount of myopia, age, or sex.
Conclusion: Refractive stability was achieved from 6 to 12 months in most eyes; a few required 18 months to stabilize. Groups IIA and III continued to be stable; Groups HB and III No Nitrogen showed mild regression that was not statistically significant.