title: Intraocular pressure measurement by three different tonometers in primary congenital glaucoma.
abstract: OBJECTIVE
  To determine the agreement between intraocular pressure (IOP) measurements using an automated non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), and the ocular response analyzer (ORA) in subjects with primary congenital glaucoma (PCG).
  
  
  METHODS
  Twenty-nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal-compensated IOP (IOPcc), Goldmann-correlated IOP (IOPg), corneal hysteresis (CH), and corneal resistance factor (CRF). A difference more than 1.5 mmHg for IOP was considered as clinically relevant.
  
  
  RESULTS
  Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD) was 15.3 ± 2.8 mmHg (GAT), 15.5 ± 6.0 (NCT), 19.2 ± 7.0 (IOPg), and 21.1 ± 7.9 (IOPcc); (P = 0.001). Except for NCT vs. GAT (P = 1.0), the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were - 10.2 to 10.3 mmHg (NCT vs. GAT), -7.8 to 15.3 (IOPg vs. GAT), and - 8.1 to 19.0 (IOPcc vs. GAT). The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P < 0.001, for IOPg vs. GAT; and r = 0.806, P < 0.001, for IOPcc vs. GAT). CH showed a significant association with differences in IOP measurements only for IOPcc vs. GAT (r = 0.830, P < 0.001).
  
  
  CONCLUSIONS
  Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.
authors.affiliation: Department of Optometry, International Branch, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Athar
authors.initials: A
authors.lastname: Zareei
authors.affiliation: Poostchi Ophthalmology Research Center, Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Razeghinejad
authors.affiliation: Poostchi Ophthalmology Research Center, Department of Ophthalmology, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohammad Hosein
authors.initials: MH
authors.lastname: Nowroozzadeh
authors.affiliation: Department of Optometry, Rehabilitation School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Yadollah
authors.initials: Y
authors.lastname: Mehrabi
authors.affiliation: Department of Optometry, Rehabilitation School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Aghazadeh-Amiri
keywords: Goldmann Applanation Tonometer; Intraocular Pressure; Noncontact Tonometer; Ocular Response Analyzer; Primary Congenital Glaucoma