Risk factors for progression to penetrating keratoplasty in patients with keratoconus

Abstract

Purpose: To determine clinical and demographic risk factors for corneal transplantation in keratoconus patients.

Design: Case control study.

Setting: Tertiary referral center.

Study population: All keratoconic eyes presenting to the Duke University Eye Center from January 1, 1997, to December 31, 2002. OBSERVATION PROCEDURE AND OUTCOME MEASURES: Cases were defined as eyes undergoing transplantation during the study period for keratoconus. Controls were defined as eyes that did not undergo transplantation. Cases were compared with controls to determine clinical and demographic risk factors for corneal transplantation.

Results: A total of 131 eyes with keratoconus were studied; 59 cases were compared with 72 controls. Groups were similar with respect to sex and race. Significant univariate risk factors for corneal transplantation were best-corrected vision worse than 20/40 (OR 3.2, 95% CI 1.1 to 9.8), cylinder >10.0 diopters (OR 3.5, 95% CI 1.0 to 12.4), and average keratometry >55 diopters (OR 5.6, 95% CI 1.4 to 21.9). In multivariate analysis, age 30 or younger conferred a sevenfold increased risk of transplantation compared with ages of more than 40 (OR 7.7 for ages 21 to 30 and OR 25.8 for ages < or = 20). Multivariate analysis also showed duration of disease 5 years or less and steep average keratometry as significant risk factors.

Conclusions: A subset of young keratoconic patients with high keratometry values may represent an underrecognized risk group for corneal transplantation. Best-corrected visual acuity worse than 20/40 at presentation and astigmatism are other clinical indicators of increased risk of corneal transplantation in keratoconus patients.