Corneal epithelial permeability: ethnic differences between Asians and non-Asians.

ABSTRACT

PURPOSE: To ascertain whether a difference in the permeability of the corneal epithelium to fluorescein (Pdc) exists between Asians and non-Asians. METHODS: From a multi-study database we extracted 632 records of baseline, open-eye Pdc measurements taken on both eyes of 176 subjects. Subjects were awake for a minimum of 4h before measurement, and were free of ocular disease and central corneal staining. Pdc was transformed by natural logarithm to better approximate normality for statistical tests. RESULTS: The mean ln(Pdc) in the Asian group was significantly greater than in the non-Asian group [-2.34 ln(nm/s) vs. -2.58 ln(nm/s); p<0.001]. CONCLUSIONS: Compared with non-Asians, Asians exhibited a less negative ln(Pdc), which translates to a higher Pdc and a more permeable corneal epithelium. We speculate that this may be related to anatomic differences responsible for greater eyelid tension in Asians.