Extended Long-Term Results of Penetrating Keratoplasty for Keratoconus

Purpose: To investigate the extended long-term results of penetrating keratoplasty (PK) for keratoconus. Methods: The subjects were all patients with clinical keratoconus who underwent initial PK at University of Tokyo from 1971 to 1990 and whose medical records were available. Data were retrieved from the medical records. Kaplan-Meier survival analysis was performed to estimate the cumulative probability of immune reaction-free grafts and graft survival. Results: One hundred twenty-five eyes in 125 patients met the entry criteria. The average age at the time of PK was 25.0 +/- 8.9 years. With an average follow-up period of 15.3 +/- 9.7 years, 12 eyes (9.6%) experienced rejection and 5 eyes (4.0%) experienced graft failure. Average best-corrected visual acuity in logarithm of the minimum angle of resolution at preoperation, 10, 20, and 25 years after surgery was 1.54 +/- 0.68, 0.06 +/- 0.22, 0.03 +/- 0.17, and 0.14 +/- 0.42, respectively. The cumulative probability of graft survival at 10, 20, and 25 years after PK was 98.8%, 97.0%, and 93.2%, respectively. Conclusions: Recovery of visual acuity was good after PK for keratoconus in an extended follow-up. The graft survival rate, however, gradually decreased 20 years after PK.