title: Comparison of ocular response analyzer parameters in chinese subjects with primary angle-closure and primary open-angle glaucoma.
abstract: OBJECTIVE
  To evaluate corneal hysteresis (CH) and intraocular pressure (IOP) measured by the Ocular Response Analyzer in Chinese subjects with primary angle-closure glaucoma (PACG), assess their relationship with Goldmann applanation tonometry (GAT) measurements, and compare this with subjects with primary open-angle glaucoma (POAG) and normal controls.
  
  
  METHODS
  In this prospective observational study, consecutive subjects with PACG and POAG without prior intraocular surgery were enrolled from glaucoma clinics. Normal subjects were recruited from an ongoing population-based study. One eye of each subject underwent standardized ocular examination and IOP measurement by GAT and the Ocular Response Analyzer. Corneal hysteresis and corneal-compensated IOP were compared between groups.
  
  
  RESULTS
  Of the 443 subjects recruited, 131 had PACG, 162 had POAG, and 150 were normal. Corneal hysteresis was lower in PACG (9.1 mm Hg; 95% confidence interval [CI], 8.7 to 9.4 mm Hg) and POAG (9.5 mm Hg; 95% CI, 9.2 to 9.5 mm Hg) eyes compared with control eyes (10.4 mm Hg; 95% CI, 10.1 to 10.6 mm Hg; P < .001 for both), with no difference (P = .16) in CH found between PACG and POAG eyes. After adjusting for age, sex, and IOP measurement by GAT, CH persisted to be lower only in eyes with PACG in comparison with control eyes (9.4 vs 10.1 mm Hg; P = .006). Eyes with POAG had lower CH than control eyes but the difference was not statistically significant (9.6 vs 10.1 mm Hg; P = .06).
  
  
  CONCLUSIONS
  Corneal hysteresis was lower in eyes with glaucoma. After adjusting for age, sex, and IOP measurement by GAT, a persistently lower hysteresis was noted in eyes with PACG compared with other groups.
authors.affiliation: Glaucoma Service, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore.
authors.forename: Arun
authors.initials: A
authors.lastname: Narayanaswamy
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Su
authors.forename: Mani
authors.initials: M
authors.lastname: Baskaran
authors.forename: Anna C S
authors.initials: AC
authors.lastname: Tan
authors.forename: Monisha E
authors.initials: ME
authors.lastname: Nongpiur
authors.forename: Hla M
authors.initials: HM
authors.lastname: Htoon
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
authors.forename: Tin
authors.initials: T
authors.lastname: Aung
mesh_terms: D000368:Aged; D044466:Asian People / Q000208:ethnology; D001696:Biomechanical Phenomena / Q000502:physiology*; D002681:China / Q000453:epidemiology; D003315:Cornea / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000208:ethnology / Q000503:physiopathology*; D005902:Glaucoma, Open-Angle / Q000208:ethnology / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014065:Tonometry, Ocular