Repeated PRK safe for treating regression, undercorrection

TAMPERE, Finland — Repeated photorefractive keratectomy was safe and effective for treating regression and undercorrection in eyes with low residual myopia after initial PRK procedures, a retrospective study here found.

Surgeons identified 63 eyes of 55 patients (from a series of 533 patients) who were retreated with PRK because of initial regression or undercorrection. The mean interval between initial PRK and secondary PRK was about 17 months.

The surgeons added 30% to the ablation nomogram when the attempted correction was programmed, based on clinical impressions of regression tendencies in retreated eyes.

All but one eye had low residual myopia (less than -5 D); the remaining eye had a residual myopia of -10.5 D. In the group of eyes with low residual myopia, the mean refraction 1 year after re-treatment was -0.42 D, and 43 eyes (86%) were within 1 D of emmetropia. Uncorrected visual acuity of 20/40 or better was achieved in 43 eyes (86%) after 1 year. One eye lost two lines of acuity because of haze. Mean haze was the same before and 1 year after re-treatment.

The eye with high residual myopia also exhibited high regression after re-treatment. One year after re-treatment, the eye had regressed to -9.5 D with a grade 2 haze.

The study is published in the March/April issue of Journal of Refractive Surgery.