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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 Pdcmeasurements 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. Pdcwas 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

Author(s): Lin, Meng C; Yeh, Thao N; Graham, Andrew D; Truong, Tan; Hsiao, Carol; Wei, Guan; Louie, Audrey | Abstract: PurposeTo determine the effects on corneal epithelial permeability and ocular response of 30 nights of continuous wear (CW) of gas permeable (GP) and silicone hydrogel (SiH) contact lenses.MethodsNinety-one subjects successfully completed 30 days of CW of either GP (n = 42) or SiH (n = 49) contact lenses. Epithelial permeability (P(dc)) was measured by scanning fluorometer at an afternoon (PM) baseline session and again the next morning (AM). One randomly selected eye of each subject was patched overnight and the patch removed immediately before the AM visit. P(dc) measurements and ocular examinations were conducted at baseline and after 30 days of CW.ResultsEpithelial permeability increased significantly after 30 days of CW in the patched eyes of the GP group (P = 0.022) and in the unpatched eyes of the SiH group (P = 0.004). The increase was driven primarily by the Asian subjects in each group (GP, P = 0.015; SiH, P = 0.001). There was no significant increase in either lens group in the non-Asian subjects. Multivariate models suggest that the change in AM P(dc) from baseline to 30 days of CW was also related to lens type (P = 0.035), time awake before measurement (P = 0.001), palpebral aperture size (P = 0.003), lens deposits (P = 0.020), and horizontal lens bearing (P = 0.003).ConclusionsSubclinical increases in epithelial permeability can be caused by contact lens CW, despite the elimination of hypoxia. GP lenses permit recovery of the epithelium more quickly than do SiH lenses. Asians appear to be more susceptible to contact lens-induced epithelial changes than do non-Asians.