Longitudinal Analysis of the Fellow Eyes in Unilateral Keratoconus

Abstract

Abstract: : Purpose: To determine the rate at which clinically normal eyes in unilateral keratoconus (KC) patients develop KC and to identify associated risk factors Methods: We prospectively recruited 778 patients with KC and 252 normal controls. 116 of 778 patients (14.9%) were diagnosed as clinically unilateral keratoconus. Both eyes of these unilateral patients were followed longitudinally for 8 years. Quantitative indices (CK, IS and KISA), qualitative patterns from topography, contact lens wear and other known risk factors were analyzed Results: 30 out of 85 (35.3%) fellow eyes developed KC with 25 of the 30 (83.3%) developing KC within the first 6 years after the initial diagnosis. The median time to the development of KC was 16.69 years (95% C.I.). Fellow eyes with higher IS value or log(KISA) values had higher risk for developing KC. Different videokeratography patterns also showed the significantly different risk for developing KC (P=0.03), especially the AB/SRAX pattern. Conclusions: Estimated from the survival analysis, about 50% fellow eyes will progress to KC within 16 years. The greatest risk is during the first six years of the onset. Videokeratography indices and patterns are useful for predicting this progression.

Keywords: keratoconus • cornea: clinical science • topography