title: Evaluation of Goldmann applanation tonometry, rebound tonometry and dynamic contour tonometry in keratoconus.
abstract: OBJECTIVE
  To compare the intraocular pressure (IOP) measurements obtained with the rebound tonometry (RT), dynamic contour tonometry (DCT) and Goldmann applanation tonometry (GAT) in keratoconic corneas and to investigate the effects of central corneal thickness (CCT) and corneal radius of curvature (CR) on IOP measurements.
  
  
  METHODS
  Sixty-three eyes of 63 keratoconus patients were enrolled in this cross-sectional study. IOP was measured on each subject always in the same order, ICare RT-Pascal DCT-GAT, after a minimum interval of 10min between measurements. CCT and CR were measured using a rotating Scheimpflug camera before the IOP measurements in all subjects. One way repeated measures ANOVA and Pearson correlation coefficient analysis was used for the statistical assessment.
  
  
  RESULTS
  Mean IOP for all enrolled eyes was 11.72±2.59mmHg for GAT, 9.34±3.29mmHg for RT, and 15.42±3.31mmHg for DCT. There were statistically significant differences among the three tonometers; GAT and RT (P<0.001), GAT and DCT (P<0.001), and RT and DCT (P<0.001). GAT and RT were significantly positively correlated with CCT (r=0.288, P=0.025 and r=0.483, P<0.001, respectively). RT was also significantly positively correlated with CR (r=0.550, P<0.001). DCT was not significantly correlated with CCT (r=0.115, P=0.377) nor CR (r=-0.179, P=0.168).
  
  
  CONCLUSIONS
  DCT has overestimated but RT has underestimated IOP readings according to GAT measurements in keratoconic corneas. DCT may be the most appropriate tonometer to use in keratoconus for the measurements of IOP, because DCT do not appear to be dependent upon CCT and CR.
authors.affiliation: Department of Ophthalmology, Dumlupinar University School of Medicine, Kutahya 43270, Turkey. Electronic address: fatihozcura@yahoo.com.
authors.forename: Fatih
authors.initials: F
authors.lastname: Özcura
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University School of Medicine, Eskisehir 26480, Turkey.
authors.forename: Nilgün
authors.initials: N
authors.lastname: Yıldırım
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University School of Medicine, Eskisehir 26480, Turkey.
authors.forename: Emre
authors.initials: E
authors.lastname: Tambova
authors.affiliation: Department of Ophthalmology, Eskisehir Osmangazi University School of Medicine, Eskisehir 26480, Turkey.
authors.forename: Afsun
authors.initials: A
authors.lastname: Şahin
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003315:Cornea / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D007640:Keratoconus / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000379:methods*; D055815:Young Adult
keywords: Central corneal thickness; Corneal curvature; Curvatura de la córnea; Espesor central de la córnea; Keratoconus; Queratocono; Tonometry; Tonometría