title: Gender- and age-related differences in corneal topography.
abstract: OBJECTIVE
  To investigate gender- and age-related differences in the corneal topography of a normal population.
  
  
  METHODS
  One hundred thirty-two topographic examinations were collected from 100 patients ranging in age from 23 to 83 years (average, 57.35+/-17.38 years). Data were segregated by gender and further divided into younger (less than 50 years) and older (50 years or more) age groups. The topographic indices of Surface Regularity Index, Surface Asymmetry Index, Irregular Astigmatism Index, Standard Deviation of Corneal Power, Corneal Eccentricity Index, Coefficient of Variation of Corneal Power, Simulated Keratometry 1 and 2, and Average Corneal Power were examined. The astigmatism pattern and corneal irregularity were determined and compared with respect to gender and age.
  
  
  RESULTS
  The corneas of older men were flatter than those of older women (p < 0.001). The vertical corneal meridian, but not the horizontal meridian, showed statistically significant gender-related changes with aging (p < 0.001). Older men had a significantly higher potential for against-the-rule astigmatism than women (p < 0.001). Corneal irregularity (measured in terms of the Surface Regularity Index and Irregular Astigmatism Index) increased with age (p < 0.001 and p < 0.001, respectively), although there was no gender-related difference. In the younger group, no gender-related differences in corneal curvature or astigmatism pattern were found.
  
  
  CONCLUSIONS
  Aging influences changes in patterns of astigmatism differently in men and women. Decreases in levels of sex hormones may play a role in gender-related changes in corneal structure with age.
authors.affiliation: Lions Eye Research Laboratories, LSU Eye Center, Louisiana State University Health Sciences Center, New Orleans 70112-2234, USA.
authors.forename: T
authors.initials: T
authors.lastname: Goto
authors.forename: S D
authors.initials: SD
authors.lastname: Klyce
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.forename: N
authors.initials: N
authors.lastname: Maeda
authors.forename: T
authors.initials: T
authors.lastname: Kuroda
authors.forename: C
authors.initials: C
authors.lastname: Ide
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D001251:Astigmatism / Q000378:metabolism / Q000503:physiopathology; D003315:Cornea / Q000502:physiology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors