On-lay lamellar keratoplasty for the treatment of keratoconus.

On-lay lamellar keratoplasty was performed in 29 patients who had keratoconus. Twelve patients (greater than 1 year follow-up) showed an average decrease in keratometry of 9.13 +/- 2.02 (mean +/- SE) D; 6 patients (6-11 months follow-up) showed an average of 10.15 +/- 2.88 D. Visual acuity continued to improve for about one year after surgery. Six patients with best visual acuities of 20/20 before surgery showed an average visual acuity of 20/29 +/- 11 (mean +/- SD) 4 months after surgery; 4 with more than a year of follow-up achieved an average of 20/26 +/- 9. Four patients with 20/40 preoperatively achieved an average of 20/63 +/- 33 four months after surgery; 3 with more than a year of follow-up showed an average of 20/38 +/- 13. All patients with successful grafts can now tolerate contact lenses for daily wear.