title: Evaluation of three applanation tonometers in dogs.
abstract: The Mackay-Marg, Tono-Pen, and Challenger applanation tonometers were evaluated in vivo in 12 clinically normal eyes of 6 dogs. Tonometric measures of intraocular pressure (IOP) were compared with closed manometric IOP measurements from the anterior chamber of anesthetized dogs. The tonometers were evaluated at IOP that ranged from 5 to 100 mm of Hg. The Mackay-Marg tonometer was the most reliable instrument when evaluated at IOP from 5 to 100 mm of Hg (r2 = 0.996) and from 10 to 30 mm of Hg (r2 = 0.962). The Tono-Pen tonometer was also reliable (r2 = 0.967) over the range of IOP, but consistently overestimated IOP at lower pressures and underestimated IOP at higher pressures. The Mackay-Marg and Tono-Pen measurements were essentially linear. When evaluated from 10 to 30 mm of Hg, r2 was 0.828 for the Tono-Pen tonometer. The Challenger tonometer, although reliable over the full range of IOP (r2 = 0.965), proved to be less accurate, as indicated by lack of a good linear equation.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0126.
authors.forename: D R
authors.initials: DR
authors.lastname: Priehs
authors.forename: G G
authors.initials: GG
authors.lastname: Gum
authors.forename: R D
authors.initials: RD
authors.lastname: Whitley
authors.forename: L E
authors.initials: LE
authors.lastname: Moore
mesh_terms: D000818:Animals; D004285:Dogs / Q000502:physiology*; D007429:Intraocular Pressure; D014065:Tonometry, Ocular / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*