A PROSPECTIVE MULTICENTER TRIAL OF EXCIMER-LASER PHOTOTHERAPEUTIC KERATECTOMY FOR CORNEAL VISION LOSS

PURPOSE: The 193-nm argon fluoride excimer laser can remove corneal sc ars and smooth corneal irregularities, obviating corneal transplantati on. We conducted a prospective multicenter trial of excimer laser phot otherapeutic keratectomy for corneal vision loss as a basis for Food a nd Drug Administration premarket approval. METHODS: We treated 232 eye s of 211 patients with corneal vision loss, All had corneal pathology in the anterior 100 mu m of the stroma, Mean postoperative follow-up w as 10 +/- 8 months, The primary outcome variable was change in best sp ectacle-corrected visual acuity. RESULTS: At postoperative month 12, b est spectacle-corrected visual acuity improved in 46 (45%) of 103 eyes and worsened in nine (9%) of 103 eyes by 2 or more Snellen lines, Bes t spectacle-corrected visual acuity improved by a mean of 1.6 +/- 2.8 Snellen lines (95% confidence interval, 1.1 to 2.1 lines), Every posto perative visit confirmed statistically significant improvement of mean best spectacle-corrected acuity. At month 12, treated eyes had a mean hyperopic shift in refraction of 0.87 diopter and a mean reduction in astigmatism of 0.36 diopter, Treatment appeared most effective in eye s with hereditary corneal dystrophies, Salzmann's nodular degeneration , and corneal scars, and least effective in eyes with calcific band ke ratopathy, Complications included recurrence of underlying pathology, corneal graft rejection, and bacterial keratitis. CONCLUSIONS: Argon f luoride excimer laser phototherapeutic keratectomy is effective, with relatively few complications, for treating vision loss from corneal op acification or irregularity, Efficacy, however, varies widely dependin g upon individual eyes and underlying diagnoses.