title: Corneal epithelial permeability: ethnic differences between Asians and non-Asians.
abstract: OBJECTIVE
  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.
authors.affiliation: Clinical Research Center, School of Optometry, University of California, Berkeley, CA, USA.
authors.forename: Wing Y
authors.initials: WY
authors.lastname: Li
authors.forename: Carol
authors.initials: C
authors.lastname: Hsiao
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Graham
authors.forename: Meng C
authors.initials: MC
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People / Q000706:statistics & numerical data*; D002140:California / Q000208:ethnology; D019573:Epithelium, Corneal / Q000378:metabolism*; D005260:Female; D019793:Fluorescein / Q000493:pharmacokinetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010539:Permeability; D055815:Young Adult
chemical_list: D019793:Fluorescein
keywords: Corneal epithelial permeability; Ethnicity; Fluorometry; Race; Shear stress