Retreatment after photorefractive keratectomy for low myopia.

Abstract

The purpose of the study was to evaluate the results of retreatment for low myopia after primary photorefractive keratectomy (PRK). A prospective study. A total of 48 eyes of 37 patients from 566 eyes of 331 patients originally treated for myopia of up to -6 diopters (D) were studied. Photorefractive keratectomy by the Coherent Schwind Keratom II excimer laser was performed. The parameters evaluated were visual acuity, refraction, and corneal clarity. Of the 566 eyes with myopia up to -6 D, 48 eyes (8.5%) required retreatment. The sphere (mean +/- standard deviation) was -0.88 +/- 1.24 D before second surgery. At 6 months, the mean was -0.04 +/- 0.91; at 1 year, it was -0.33 +/- 0.75 D. At 6 months, 75% of sphere value was within +/- 1 D. The preoperative uncorrected visual acuity (UCVA) was 20/200 or worse in 12.8% of eyes and 20/40 or better in 40.4% of eyes. Six months after reoperation, 20/60 UCVA was obtained in 17.4% of eyes. All others (82.6%) had UCVA of 20/40 or better, 26.1% better than 20/20. The proportion of eyes with best spectacle-corrected visual acuity better than 20/20 decreased from 60.0% to 47.1% 6 months after reoperation. Six months after reoperation, haze 1 was present in 42.9% and haze 2 in 4.7% of eyes, and in no eye was haze worse. Retreatment after PRK for low myopia can significantly increase UCVA and decrease residual refractive error without significant complications.