title: Estimation of intraocular pressure in rabbits with commonly used tonometers.
abstract: To validate accuracy and reproducibility of the Perkins tonometer, pneumatonometer, and Tono-Pen XL (Medtronic Solan, Jacksonville, FL) in estimating intraocular pressure (IOP) in rabbits.
  
  
  
  IOP was increased from 5 to 50 mm Hg in 5-mm increments. Measurements were compared to readings of two digital manometers simultaneously measuring real IOP in the anterior chamber and vitreous cavity. Interobserver accuracy was evaluated using 4 eyes with the Perkins tonometer.
  
  
  
  The Perkins tonometer and Tono-Pen XL underestimated IOP and were more accurate at pressures less than 30 mm Hg. No statistically significant difference was found between real IOP and Tono-Pen XL readings. The pneumatonometer overestimated pressures in the low ranges but was accurate at pressures greater than 40 mm Hg. The Tono-Pen XL had more variability than the Perkins tonometer and pneumatonometer at high IOP.
  
  
  
  None of the tonometers are accurate or reproducible in estimating IOP in rabbits over the tested range. Pneumatonometry, although not very accurate, has the advantage of having acceptable variability.
authors.affiliation: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami, Miller School of Medicine, 1638 NW10th Avenue, Miami, FL 33136, USA.
authors.forename: Ana C
authors.initials: AC
authors.lastname: Acosta
authors.forename: Edgar M
authors.initials: EM
authors.lastname: Espana
authors.forename: Izuru
authors.initials: I
authors.lastname: Nose
authors.forename: Marcia
authors.initials: M
authors.lastname: Orozco
authors.forename: Hideo
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Anna S
authors.initials: AS
authors.lastname: Venkatraman
authors.forename: Francisco
authors.initials: F
authors.lastname: Fantes
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Parel
mesh_terms: D000818:Animals; D003315:Cornea / Q000033:anatomy & histology; D004867:Equipment Design; D007429:Intraocular Pressure / Q000502:physiology*; D015588:Observer Variation; D011817:Rabbits; D015203:Reproducibility of Results; D014065:Tonometry, Ocular / Q000295:instrumentation*