Extended long-term outcomes of penetrating keratoplasty for keratoconus

Abstract

Objective: To report graft survival results for initial penetrating keratoplasty (PK) performed more than 20 years ago for keratoconus. Secondary outcome measures included recurrent keratoconus, best spectacle-corrected visual acuity (BSCVA), and rates of glaucoma.

Design: Retrospective, consecutive, noncomparative case series.

Participants: All patients with clinical and histopathological keratoconus who underwent initial PK at the University of Iowa Hospitals and Clinics from 1970 to 1983. Patients with pellucid marginal degeneration were excluded.

Methods: At baseline, age, preoperative BSCVA, keratometric astigmatism, and host/donor graft sizes for each eye were recorded. Visual acuity and intraocular pressure were followed until the eyes reached 1 of 4 end points: graft failure, recurrent keratoconus, loss to follow-up, or death. Kaplan-Meier survival analysis was performed to estimate the long-term probability of graft failure and recurrent keratoconus.

Results: Among the 112 eyes of 84 patients who met entry criteria, there was a mean age at transplant of 33.7 years and preoperative BSCVA of 20/193. With a mean follow-up of 13.8 years (range, 0.5-30.4), 7 eyes (6.3%) experienced graft failure. Recurrent keratoconus was confirmed clinically or histologically in 6 eyes (5.4%), with a mean time to recurrence of 17.9 years (range, 11-27). Kaplan-Meier analysis estimated a graft survival rate of 85.4% and a rate of recurrent keratoconus of 11.7% at 25 years after initial transplantation. Six eyes (5.4%) developed open-angle glaucoma, and 2 eyes required trabeculectomy. At the last follow-up visit, 82 eyes (73.2%) had BSCVA of 20/40 or better.

Conclusion: Penetrating keratoplasty offers good long-term visual rehabilitation for keratoconus. Relative to other indications for PK, there is a low rate of graft failure. Late recurrence of disease occurs with increasing frequency over time. Given the younger age at which keratoconus patients undergo corneal transplantation, these long-term findings should be incorporated into preoperative counseling.