title: Can higher end tonometers be used interchangeably in routine clinical practice?
abstract: BACKGROUND
  Precise intraocular pressure (IOP) measurement is important in glaucoma practise. Various instruments are available today to accurately measure IOP. Thus, the question arises about which instrument to use and whether all of them can be used interchangeably.
  
  
  OBJECTIVE
  To assess the agreement between noncontact tonometer (NCT), rebound tonometer (RBT), Goldmann applanation tonometer (GAT), and dynamic contour tonometer (DCT) in measuring IOP.
  
  
  METHODS
  499 eyes of 250 patients were evaluated during a period of 24 months from September 2010 to August 2012 and measurement of IOP by NCT, RBT, GAT, and DCT was done in the given sequence. The agreement was assessed by use of the Bland-Altman plot keeping GAT as a gold standard technique.
  
  
  RESULTS
  The mean IOP value of NCT, RBT, GAT, and DCT was 15.9 ± 5.5, 15.9 ± 5.8, 15.9 ± 4.9, and 16.0 ± 4.7 mm of Hg, respectively. The limits of agreement of GAT with DCT, NCT, and RBT were found to be +5.4 to -5.2, -4.7 to +4.6, and -5.2 to +5.1 mm of Hg, respectively.
  
  
  CONCLUSIONS
  A positive and strong correlation was found between newer tonometers and GAT, but the limit of agreement was clinically unacceptable. The use of a single tonometer should be practised at a glaucoma clinic for a patient at each follow-up.
authors.affiliation: Department of Ophthalmology, Government Medical College, Surat, Gujarat, India.
authors.forename: Kunjan Jayantilal
authors.initials: KJ
authors.lastname: Patel
authors.forename: Saurabh P
authors.initials: SP
authors.lastname: Jain
authors.forename: Priti R
authors.initials: PR
authors.lastname: Kapadia
authors.forename: Nikunj V
authors.initials: NV
authors.lastname: Patel
authors.forename: Saurabh
authors.initials: S
authors.lastname: Patel
authors.forename: Vikas
authors.initials: V
authors.lastname: Patel
mesh_terms: D000328:Adult; D005260:Female; D005901:Glaucoma / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis / Q000503:physiopathology; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation*; D014792:Visual Acuity / Q000502:physiology