title: IOP measured by dynamic contour tonometry correlates with IOP measured by Goldmann applanation tonometry and non-contact tonometry in Japanese individuals.
abstract: OBJECTIVE
  The purpose of this study was threefold. We sought to compare the intraocular pressure (IOP) measured by dynamic contour tonometry (DCT) with that measured by Goldmann applanation tonometry (GAT) and noncontact tonometry (NCT). We also examined the influence of central corneal thickness (CCT) and corneal curvature radius (CCR) on the IOP measurements. Last, we investigated the factors that could affect the ocular pulse amplitude (OPA) measurements.
  
  
  METHODS
  Seventy-four patients with no history of intraocular surgery were enrolled in this study. We measured IOP by DCT, GAT, and NCT, and the CCT, CCR, and axial length (AL) in the right eye of each patient. We also measured OPA by DCT. We subsequently analyzed the correlation of IOP measurements between GAT and DCT and between NCT and DCT. We also examined the influence of CCT, CCR, and AL on IOP readings by the 3 tonometers. In addition, we investigated the factors that could affect the OPA measurements.
  
  
  RESULTS
  The mean IOP measured by DCT was 2.8 mm Hg higher than that by GAT and 3.2 mm Hg higher than that by NCT. This difference was greater with thinner CCT in the lower IOP group than in the higher IOP group. IOP measurements by both GAT and NCT significantly correlated with CCT; however, IOP measurement by DCT did not correlate with CCT. No significant correlations were shown between the IOP measured by each of the 3 tonometers and either CCR or AL. OPA measurements positively correlated with age, IOP measurement by DCT, and pulse pressure.
  
  
  CONCLUSIONS
  IOP measured by DCT correlates with IOP measured by GAT or NCT with a roughly 3.0 mm Hg higher value, and these differences were greater in the patients with a thinner CCT. IOP measurements by both GAT and NCT significantly correlated with CCT; however, IOP measurement by DCT did not correlate with CCT. Our findings also indicate that OPA measured using DCT shows a positive correlation with patient age, IOP measurement by DCT, and pulse pressure.
authors.affiliation: Department of Ophthalmology, School of Medicine, University of Occupational and Environmental Health, Japan. itoken29@yahoo.co.jp
authors.forename: Ken
authors.initials: K
authors.lastname: Ito
authors.forename: Akihiko
authors.initials: A
authors.lastname: Tawara
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kubota
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Harada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D001794:Blood Pressure / Q000502:physiology; D002648:Child; D003315:Cornea / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D057066:Low Tension Glaucoma / Q000175:diagnosis / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014065:Tonometry, Ocular / Q000295:instrumentation*; D014463:Ultrasonography; D055815:Young Adult