Identifying relationships between tomography-derived corneal thickness, curvature, and diameter and in vivo confocal microscopic assessment of the endothelium in healthy corneas of young adults.

PURPOSE: Despite the importance of a healthy endothelial layer in anterior segment surgery, the possible influence of corneal parameters on endothelial cell density (ECD) has largely been ignored in the young adult eye. This study investigated the possible associations between corneal tomographic parameters and ECD values in young adults. METHODS: Subjects aged 21-30 years, with normal corneas were recruited. Mean ECD, mean cell area (MCA), coefficient of variation for cell area (COVA), and proportion of hexagonal cells were derived by in vivo confocal microscopy. The Orbscan II system was used to measure corneal parameters including: thickness, horizontal corneal diameter, corneal curvature, anterior and posterior elevation, and eccentricity. RESULTS: Sixty-two subjects (42 female, 20 male) were included (mean age 25+/-3 years). Overall mean ECD was 3169+/-309 cells/mm(2) with no differences between genders. Mean percentage of hexagonality was 53+/-5%, male subjects (55%) had a higher percentage of hexagonal cells than female subjects (51%) (P=0.02). Central corneal thickness (CCT) was 529+/-43 microm. Central ECD was significantly correlated with CCT (Pearson's r=0.26, P=0.04). However, horizontal corneal diameter (r=0.19, P=0.14), anterior corneal curvature (r=-0.07, P=0.6), and posterior corneal curvature (r=-0.07, P=0.6) were not correlated with ECD or percentage of hexagonality. There was no statistically significant association between anterior chamber depth (3.6+/-0.3 mm) and ECD (r=0.15, P=0.3). CONCLUSION: Corneal thickness is related to ECD in normal young adult eye, with lower ECD values identified in thinner corneas; however, corneal diameter and corneal curvature do not have a significant correlation with ECD.