White-to-white corneal diameter in the Tehran Eye Study.

Cornea 29(1):9-12 (2010) PMID 19907300

PURPOSE: To determine the mean corneal diameter and its determinants in the population of Tehran. METHODS: From the Tehran Eye Study participants who were sampled through a stratified cluster approach, those in the first 4 municipality districts of Tehran were selected, and after applying the inclusion and exclusion criteria, 399 right eyes and 401 left eyes of 410 people aged 14 years and older were examined with the Orbscan II. The corneal diameter was defined as the horizontal limbus-to-limbus distance. Linear regression was used to detect separate and multiple correlations. The design effect of cluster sampling was also considered and adjusted for. RESULTS: The studied participants were male in 38.80%, and their mean age was 40.68 +/- 16.80 years. The mean corneal diameter was 11.68 mm (95% confidence interval: 11.63-11.73). The 95% range (mean +/- 2 SDs) was 10.76-12.60 mm. The mean corneal diameter was 11.76 and 11.63 mm in males and females, respectively. The corneal diameter in the studied population had no significant correlation with age (P = 0.186) but showed an increase of 0.18 mm for each millimeter increase in the anterior chamber depth (P = 0.028). CONCLUSION: Although the mean corneal diameter in the present population was not different from that reported in other studies, the data suggest that slightly different cutoff values for the definition of macrocornea (>12.60 mm) and microcornea (<10.76 mm) can be used with this population.