title: Assessment of a new Goldmann applanation tonometer.
abstract: OBJECTIVE
  The classic Goldmann applanation tonometer (GAT) has been further developed by Haag-Streit International. The applanation principle has been retained, while the internal force transmission and the pressure gauging have been optimised, the display of results digitised. The authors compared the GAT standard with the new GAT digital.
  
  
  METHODS
  Four fixed tonometer pairs were used. The protocol included: non-contact pachymetry, slit-lamp examination, three consecutive measurements with each tonometer with a 5 min interval in between, check for side effects in 15 min. Three groups (intraocular pressure (IOP) levels) were defined: (1) IOP ≤ 16; (2) IOP>16 and <23; (3) IOP ≥ 23 mm Hg.
  
  
  RESULTS
  125 Patients (250 eyes) were evaluated. IOP (mm Hg), GAT standard versus GAT digital, for the rights eyes was: Group 1: 12.94 ± 0.55 versus 13.11 ± 0.53, p=0.71. Group 2: 18.26 ± 0.59 versus 18.03 ± 0.52, p=0.53; Group 3: 30.28 ± 0.48 versus 30.42 ± 0.41, p=0.97; all right eyes: 17.48 ± 7.48 versus 17.73 ± 7.4, p=0.99. For the left eyes, there was no significant difference, either. The correlation was very good and was not influenced by the IOP level. The Pearson coefficient for the right eye was 0.985, and for the left eye 0.994. In the Bland-Altman analysis, although there were two single readings that differed by as much as 5 mm Hg, GAT digital measures showed almost no skew, and the mean difference was 0.03 ± 1.23 mm Hg (n=250). A multiple regression analysis showed no influence of order of measurement, eyeside or pachymetry.
  
  
  CONCLUSIONS
  The new GAT digital is as reliable and safe as GAT standard. IOP values correlate well. It offers a digitised display and a wireless transfer of data. The display of values up to the first decimal digit is not necessarily associated with a more precise measurement, but may offer an additional comfort compared with the 2 mm Hg scale of the classic GAT.
authors.affiliation: Department of Ophthalmology, University of Bern, Inselspital, Bern 3010, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Egli
authors.forename: D
authors.initials: D
authors.lastname: Goldblum
authors.forename: A
authors.initials: A
authors.lastname: Kipfer
authors.forename: K
authors.initials: K
authors.lastname: Rohrer
authors.forename: C
authors.initials: C
authors.lastname: Tappeiner
authors.forename: M
authors.initials: M
authors.lastname: Abegg
authors.forename: L
authors.initials: L
authors.lastname: Berger
authors.forename: A
authors.initials: A
authors.lastname: Schoetzau
authors.forename: M E
authors.initials: ME
authors.lastname: Iliev
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000175:diagnosis*; D012015:Reference Standards; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D055815:Young Adult