The Role of Corneal Thickness in Fuchs' Endothelial Corneal Dystrophy

Abstract

Purpose: : Diseases of the anterior segment, such as Fuchs’ Endothelial Corneal Dystrophy (FECD), influence central corneal thickness (CCT), as do factors such as intraocular pressure and genetics. Increased CCT is a known late stage FECD finding; however, the association between earlier stages of FECD and CCT is less clear. We examined the relationship of FECD severity and CCT in subjects from the FECD Genetics Multi-Center Study.

Methods: : Subjects were recruited as part of a study to identify genetic factors underlying FECD and consist of index cases, family members and additional non-familial cases and controls. Subjects underwent slit lamp biomicroscopy for FECD and received a grade for each eye from 0 (no guttae) to 6 (>5mm confluent guttae with corneal edema). A total of 1662 eyes from 997 subjects were examined for associations between FECD grade and CCT measured by ultrasonic pachymetry. A multivariable model was fit to determine the effect of FECD grade on CCT, adjusting for eye, age, race, gender and familial relationship to index case. Generalized estimating equations methodology was used to account for the correlation between eyes within a subject. All comparisons are evaluated based on the relevant contrast from the model.

Results: : CCT increased with increasing FECD grade in both index cases (grades 3 or greater, p<0.01) and affected family members (grades 4 or greater, p<0.01) compared to subjects with a grade of 0. Additionally, affected family members of the same grade had, on average, thinner corneas than the index patients for FECD grades of 3, 4 or 5 (p<0.03). Age, race and gender were not found to be significantly associated with CCT.

Conclusions: : CCT increases with severity of FECD, including at grades for which corneal edema was not a notable grading criterion. For several higher grading levels, affected family members demonstrated thinner corneas than corresponding index cases. Further analysis to determine the effect of intraocular pressure on these results is in progress.

Keywords: cornea: clinical science • clinical (human) or epidemiologic studies: natural history