title: Comparison of dynamic contour tonometry and Goldmann applanation tonometry in keratoconus.
abstract: OBJECTIVE
  We performed a comparative study using Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) to measure intraocular pressure (IOP) in eyes with keratoconus.
  
  
  METHODS
  IOP was measured in 114 eyes of 75 patients with keratoconus (51 men and 24 women; mean age, 36.1 ± 11.2 years) using GAT and DCT in randomized order. Central corneal thickness (CCT), minimal corneal thickness (MCT), and corneal topography were recorded using the Pentacam. Four groups according to Amsler's keratoconus classification were composed and analyzed for significant differences of CCT, MCT, GAT, and DCT results.
  
  
  RESULTS
  Mean CCT in the 114 keratoconus eyes was 481.1 ± 46.2 μm (range, 334-601 μm). Mean MCT was 453.3 ± 56.3 μm (range, 239-573 μm). Mean IOP measured using GAT was 13.1 ± 2.9 mm Hg, whereas mean IOP measured using DCT was 14.8 ± 2.6 mm Hg. Neither the results for GAT nor those for DCT showed a significant correlation with CCT (Pearson correlation: P < 0.05). Multifactorial analysis revealed that CCT and MCT, but not GAT and DCT, results were significantly different in corneas of varying curvatures.
  
  
  CONCLUSIONS
  This study shows that DCT measures IOP higher than GAT in eyes with keratoconus. In keratoconus, both methods seem to be independent of CCT and therefore are equally, but not interchangeably, applicable when monitoring IOP. Further analysis revealed that CCT and MCT are significantly different in corneas of varying Amsler grade.
authors.affiliation: University Eye Hospital Wuerzburg, Wuerzburg, Germany. j.d.unterlauft@gmx.de
authors.forename: Jan Darius
authors.initials: JD
authors.lastname: Unterlauft
authors.forename: Nina
authors.initials: N
authors.lastname: Schädle
authors.forename: Karsten
authors.initials: K
authors.lastname: Kasper
authors.forename: Thomas
authors.initials: T
authors.lastname: Klink
authors.forename: Gerd
authors.initials: G
authors.lastname: Geerling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003315:Cornea / Q000473:pathology*; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D007640:Keratoconus / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult