Excimer retreatment for myopic photorefractive keratectomy failures. Six- to 18-month follow-up.

Purpose: To study the results of retreatment after myopic photorefractive keratectomy in 22 patients. Five patients showed regression and 17 showed undercorrection combined with regression. The follow-up was 6 to 18 months.

Methods: A laser was used with a fluence of 160 mJ/cm2 at a frequency of 5 Hz. The same nomogram used for the initial treatment was used for the retreatment. No nitrogen purge was used. Fluorometholone 0.1% four times daily tapered over 4 months was applied postoperatively except in five patients.

Results: There was no untoward effect in any patient who had retreatment. The mean preoperative spherical equivalent before retreatment was -2.61 +/- 1.62 diopters (D) (range, -1.00 to -6.63 D). After 1 year, the mean spherical equivalent was -0.84 +/- 1.22 D (range, 0.00 to -4.88 D) and at 18 months it was -1.31 +/-1.60 D (range, 0.00 to -5.13 D). Spherical equivalent was +/- D in 82% of patients at 1 year and in 67% at 18 months. Uncorrected visual acuity was 20/40 or better at 1 year in 77% of patients and 20/20 or better in 55%; at 18 months, it was 20/40 or better in 67%.

Conclusion: Retreatment may be considered for undercorrection and/or regression in photorefractive keratectomy. No complications were observed, and there is appreciable improvement in the final results. The refraction 6 months after retreatment is stable with no statistically significant change from 6 to 12 months (Student's t=0.51; P=0.62) and 6 to 18 months (Student's t=1.0l; P=0.33).