title: Comparison of goldmann applanation tonometer, noncontact tonometer, and TonoPen XL for intraocular pressure measurement in different types of glaucomatous, ocular hypertensive, and normal eyes.
abstract: OBJECTIVE
  To compare intraocular pressure (IOP) measurements by Goldmann applanation tonometer (GAT), noncontact tonometer (NCT), and TonoPen XL in glaucomatous, ocular hypertensive (OHT), and normal eyes, all with various central corneal thickness (CCT).
  
  
  METHODS
  In 508 subjects, IOP was measured by three different tonometers: GAT, NCT, and TonoPen. CCT was also measured.
  
  
  RESULTS
  There was a statistically significant difference between IOP measurements made using the three different tonometers (RMANOVA, P < 0.0001). Both NCT/GAT and TonoPen/GAT differences were significantly associated with age, CCT, IOP, and glaucoma diagnosis (multiple regression analysis, all P ≤ 0.05). CCT and IOP had the greatest effect on IOP measurement variance by different tonometers. IOP measurements made by NCT were consistently higher than those made by GAT; this difference increased both with IOP and CCT levels, but decreased with age and OHT. In addition, TonoPen overestimated the GAT in the eyes of subjects with OHT.
  
  
  CONCLUSIONS
  IOP measurement differences between the three tonometers are affected by age, type of glaucoma, and especially CCT and IOP levels.
authors.affiliation: Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Na Rae
authors.initials: NR
authors.lastname: Kim
authors.forename: Chan Yun
authors.initials: CY
authors.lastname: Kim
authors.forename: Hyunjoong
authors.initials: H
authors.lastname: Kim
authors.forename: Gong Je
authors.initials: GJ
authors.lastname: Seong
authors.forename: Eun Suk
authors.initials: ES
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003315:Cornea / Q000033:anatomy & histology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D057066:Low Tension Glaucoma / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009798:Ocular Hypertension / Q000175:diagnosis; D014065:Tonometry, Ocular / Q000295:instrumentation*