Repeated excimer laser treatment after photorefractive keratectomy.

Scarring or undercorrection occurs in a small percentage of patients after myopic photorefractive keratectomy. Scarring occurred in 1.8% of 298 patients with a baseline myopia of 6.0 diopters or less, increasing to 8.8% in those with corrections of more than 6.0 D. Undercorrection of more than 1 D occurred in 2.7% of the eyes with a baseline myopia of up to -6.0 D. A much greater incidence of undercorrection (30% to 40%) was found after corrections of more than 6.0 D. Thirty eyes in 30 patients were reoperated because of scarring (11 eyes) and/or undercorrection (27 eyes) and were observed for 6 to 18 months (average, 7.8 months). Only one of the eyes has shown mild scar formation after this second laser treatment. Sixty-three percent of these patients had a manifest refraction between -1.0 D and +1.0 D six months after reoperation. Repeated phototablation seems to be a valuable technique for treatment of undercorrection and/or scarring after photorefractive keratectomy.