title: Correlations between different tonometries and ocular biometric parameters in patients with primary congenital glaucoma.
abstract: OBJECTIVE
  To identify the correlation between the difference of intraocular pressure measurements (IOP) obtained using the Goldmann applanation tonometer (GAT) and three others tonometers (Handheld applanation tonometer - HAT, Dynamic contour tonometer - DCT and Tono-Pen®) with biometric characteristics (corneal diameter, pachymetry, keratometry and axial length) in patients with congenital glaucoma.
  
  
  METHODS
  A cross-sectional study was performed on 46 eyes from 46 patients with congenital glaucoma. IOP measurements were obtained in all patients using GAT, HAT, DCT and Tono-Pen®. Keratometry, pachymetry, biometry and corneal diameter measurements were performed after the IOP measurement. The order of the tonometries was randomized. The correlations between the differences of IOP values of GAT and the other tonometers (Delta-IOP), and the different biometric parameters were studied.
  
  
  RESULTS
  Tono-Pen® Delta IOP revealed moderate positive correlation to keratometry (r=0.41, p=0.004). The other Delta-IOPs showed no correlation with any of the biometric characteristics evaluated.
  
  
  CONCLUSIONS
  IOP differences between GAT (gold standard) and GAT, HAT, DCT or Tono-Pen tonometers seem not to correlate with majority of ocular biometric characteristics. The only exception was the keratometry, which correlated in a positive and moderate way with Tono-Pen® Delta-IOP. This result suggests that the differences of IOP values of Tono-Pen® and GAT increase with the steepness of the cornea.
authors: Marcio Henrique
authors: MH
authors: Mendes
authors: Alberto Jorge
authors: AJ
authors: Betinjane
authors: Veronica Andrea
authors: VA
authors: Quiroga
mesh_terms: D000293:Adolescent; D000328:Adult; D001699:Biometry / Q000295:instrumentation* / Q000379:methods; D002648:Child; D003315:Cornea / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000151:congenital* / Q000473:pathology; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D007640:Keratoconus / Q000175:diagnosis; D008297:Male; D009929:Organ Size; D012016:Reference Values; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods; D055815:Young Adult