Retreatment after photorefractive keratectomy for low myopia.

OBJECTIVE: The purpose of the study was to evaluate the results of retreatment for low myopia after primary photorefractive keratectomy (PRK).

DESIGN: A prospective study.

PARTICIPANTS: 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.

INTERVENTION: Photorefractive keratectomy by the Coherent Schwind Keratom II excimer laser was performed.

MAIN OUTCOME MEASURES: The parameters evaluated were visual acuity, refraction, and corneal clarity.

RESULTS: 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.

CONCLUSION: Retreatment after PRK for low myopia can significantly increase UCVA and decrease residual refractive error without significant complications.