Late onset of corneal scar after excimer laser photorefractive keratectomy.

PURPOSE: We studied the occurrence of late scarring after photorefractive keratectomy and its response to topical corticosteroids and debridement during the course of follow-up of 950 eyes that had photorefractive keratectomy with excimer laser.
METHODS: Five eyes of four patients developed localized corneal scars, decreased visual acuity, and increased myopia after five to 33 months of good visual acuity, with trace haze. In two eyes, scars were removed by debridement alone. In these two eyes, recurrent scars were treated by debridement, followed by aggressive treatment with topical corticosteroids. Two other eyes were treated with topical corticosteroids alone. The fifth eye, which developed a scar after debridement to correct a subjective visual distortion after photorefractive keratectomy, was treated with debridement followed by aggressive topical corticosteroids.
RESULTS: Treatment with topical corticosteroids alone in two eyes improved uncorrected visual acuity slightly and decreased myopia, although the scars remained unchanged. Debridement without aggressive topical corticosteroid use resulted in rapid return of the scars and a decrease in visual acuity. Subsequent debridement after aggressive topical corticosteroid treatment resulted in resolution of scars and no recurrence after discontinuation of corticosteroids in one case. In another case, the scar recurred eight months after discontinuation of topical corticosteroids. In Case 4, the scar has not recurred as the topical corticosteroid dosage has been reduced.
CONCLUSIONS: Patients who undergo photorefractive keratectomy should be counseled concerning the risk of late scarring, reexamined frequently after photorefractive keratectomy, and treated with topical corticosteroids after corneal trauma. Long-term treatment with topical corticosteroids may be required to prevent the recurrence of scars after debridement.