title: Clinical comparison of ocular blood flow tonometer, Tonopen, and Goldmann applanation tonometer for measuring intraocular pressure in postkeratoplasty eyes.
abstract: OBJECTIVE
  Intraocular pressure (IOP) measurements vary with different tonometers in irregular corneas. The purpose of our study was to determine the comparability of the ocular blood flow tonometer (OBF) and Tonopen with the Goldmann applanation tonometer (GAT) in measuring IOP in post-keratoplasty eyes.
  
  
  METHODS
  The IOP was measured using the OBF tonometer, GAT, and Tonopen in 69 post-keratoplasty eyes by two observers. The same instruments were used, and the sequence of measurements was randomized. Pachymetry to measure corneal thickness was done in all patients.
  
  
  RESULTS
  Interobserver variation for IOP measured with GAT was statistically significant ( p = 0.039). Two-way analysis of variance (ANOVA), however, did not demonstrate any statistical difference between measurements with the three tonometers and two observers. Corneal thickness did not appear to have an effect on measurements with any of the tonometers.
  
  
  CONCLUSIONS
  There was no significant difference in the overall accuracy of the OBF tonometer over the Tonopen versus the GAT. The OBF tonometer can be a useful alternative in measuring IOP in post-keratoplasty eyes.
authors.affiliation: Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom.
authors.forename: V J
authors.initials: VJ
authors.lastname: Rao
authors.forename: L
authors.initials: L
authors.lastname: Gnanaraj
authors.forename: K W
authors.initials: KW
authors.lastname: Mitchell
authors.forename: F C
authors.initials: FC
authors.lastname: Figueiredo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D003315:Cornea / Q000033:anatomy & histology; D003316:Corneal Diseases / Q000601:surgery; D005123:Eye / Q000098:blood supply*; D006801:Humans; D007429:Intraocular Pressure; D015948:Keratoplasty, Penetrating; D008875:Middle Aged; D015588:Observer Variation; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation / Q000379:methods*