title: Intraocular pressure and central corneal thickness in the COMET cohort.
abstract: OBJECTIVE
  To describe intraocular pressure (IOP) and central corneal thickness (CCT) in ethnically diverse, myopic young adults enrolled in COMET (the Correction of Myopia Evaluation Trial) and their association with ocular and demographic factors.
  
  
  METHODS
  IOP (Goldmann tonometry), CCT (handheld pachymetry), refractive error (cycloplegic autorefraction), and ocular components (A-scan ultrasonography) were measured in 385 of the original 469 subjects (mean age = 20.3 ± 1.3 years). Summary statistics for descriptive analysis, Pearson correlation coefficients, and linear regression models to formally test the association of IOP and CCT with other covariates were used.
  
  
  RESULTS
  Mean IOP was 15.1 ± 0.1 mm Hg and differed by ethnicity and CCT but did not vary by gender, magnitude of myopia, or vitreous chamber depth (VCD). Adjusting for CCT, IOP in black participants was 1.8 mm Hg higher than in Hispanics (p = 0.0001) and 0.8 mm Hg higher than in whites (p = 0.03). Mean CCT was 562.4 ± 1.8 μm and differed by ethnicity, VCD, and IOP after adjusting for covariates. Blacks had thinner corneas than Asians, whites, and Hispanics, with adjusted differences of 15.4, 11.8, and 15.3 μm (p = 0.03, < 0.01 and < 0.01), respectively. Eyes with shorter VCD (<17.8 mm) had 8.0-μm thinner CCT (p = 0.03). CCT did not vary by gender or magnitude of myopia. Overall, a modest positive correlation (r = 0.25, P < 0.0001) was found between IOP and CCT, which varied by ethnicity in Asians (r = 0.47; p = 0.008), blacks (r = 0.29; p = 0.002), and whites (r = 0.24; p = 0.002).
  
  
  CONCLUSIONS
  Myopic, black young adults had higher IOP and thinner corneas relative to other ethnic groups, suggesting that evaluation of these parameters during routine examination of these individuals should begin at a young age. Their thinner CCT should also be considered in evaluations for refractive surgery.
authors: University of Houston College of Optometry, Houston, Texas, USA. kfern@optometry.uh.edu
authors: Karen D
authors: KD
authors: Fern
authors: Ruth E
authors: RE
authors: Manny
authors: Jane
authors: J
authors: Gwiazda
authors: Leslie
authors: L
authors: Hyman
authors: Katherine
authors: K
authors: Weise
authors: Wendy
authors: W
authors: Marsh-Tootle
mesh_terms: D000293:Adolescent; D002648:Child; D003315:Cornea / Q000000981:diagnostic imaging*; D018450:Disease Progression; D004311:Double-Blind Method; D005006:Ethnicity; D005139:Eyeglasses; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007429:Intraocular Pressure; D008297:Male; D009216:Myopia / Q000208:ethnology / Q000503:physiopathology* / Q000628:therapy; D011379:Prognosis; D013781:Texas / Q000453:epidemiology; D013997:Time Factors; D014065:Tonometry, Ocular; D014463:Ultrasonography; D055815:Young Adult