Multizone photorefractive keratectomy for myopia of 8 to 23 diopters

Multizone photorefractive keratectomy (PRK) was performed on 124 eyes of 69 patients for the treatment of high myopia using 4.5 mm, 5.0 mm, and 6.0 mm diameter ablation zones. Preoperative spherical equivalent refractions ranged from -8.00 diopters (D) to -22.5 D (mean +/- SD, -12.3 +/- 3.9 D). Mean attempted ablation depth was 109.5 +/- 37.8. Follow up ranged from 6 to 9 months. An uncorrected visual acuity of 20/60 or better was achieved in 63% of eyes and 20/40 or better in 48% of eyes. Sixty-seven percent of eyes achieved their pretreatment spectacle corrected visual acuity or were within two Snellen lines of it at 6 months postop. Subepithelial haze was mild in 23% of eyes and moderate in another 34% of eyes. This cleared without a trace in almost all of these eyes within 6 months. Twenty-five percent of the eyes had dense scars and required reablation.