title: Comparison of IOP measurements between ORA and GAT in normal Chinese.
abstract: OBJECTIVE
  To compare intraocular pressure (IOP) obtained from the ocular response analyzer (ORA) and Goldmann applanation tonometer (GAT) on a group of normal Chinese.
  
  
  METHODS
  One hundred twenty-five normal subjects were recruited, with one eye randomly selected for this study. Each eye was measured first with the noncontact tonometer ORA, followed by the GAT and ultrasound pachometry, in a randomized order. Four readings were obtained from the ORA, and three measurements were taken with the GAT. The mean was used for analysis. The ORA provided a Goldmann-correlated IOP (IOPg) and a corneal-compensated IOP (IOPcc). Three central corneal thickness (CCT) values were measured using an ultrasound pachometer, and the mean was used for analysis.
  
  
  RESULTS
  IOP obtained from the ORA was similar to that from the GAT (IOPg minus GAT: mean difference = 0.33 mm Hg, 95% limits of agreement = 4.55 to -4.44 mm Hg; IOPcc minus GAT: mean difference = 0.24 mm Hg, 95% limits of agreement = 4.83 to -5.07 mm Hg). CCT was positively associated with corneal hysteresis (CH) (r2 = 0.30, p < 0.01), corneal resistance factor (r2 = 0.38, p < 0.01), GAT (r2 = 0.09, p < 0.01) and IOPg (r2 = 0.16, p < 0.01). IOPcc was not associated with CCT (r2 = 0.01, p = 0.33).
  
  
  CONCLUSIONS
  Both IOPg and IOPcc have good agreement with GAT on normal subjects. The influence of CCT on IOPcc was insignificant.
authors.affiliation: School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China. andrew.kc.lam@polyu.edu.hk
authors.forename: Andrew
authors.initials: A
authors.lastname: Lam
authors.forename: Davie
authors.initials: D
authors.lastname: Chen
authors.forename: Roger
authors.initials: R
authors.lastname: Chiu
authors.forename: Wan-Sang
authors.initials: WS
authors.lastname: Chui
mesh_terms: D000328:Adult; D044466:Asian People; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D012016:Reference Values; D014065:Tonometry, Ocular; D014463:Ultrasonography