Abstract
Objective—To determine whether an applanation tonometer and rebound tonometer can be used to detect similar intraocular pressure (IOP) measurements in eyes of dogs undergoing phacoemulsification.
Animals—24 dogs (40 eyes) undergoing elective phacoemulsification.
Procedures—IOP measurements were obtained from each eye by use of both the rebound tonometer and applanation tonometer. Central corneal thickness was measured by use of an ultrasonic pachymeter 3 hours before surgery and 2 and 24 hours after surgery. Statistical analysis was performed by use of paired t tests.
Results—Mean ± SD IOP 3 hours before surgery, 2 hours after surgery, and 24 hours after surgery was 11.9 ± 4.7 mm Hg, 15.5 ± 11.7 mm Hg, and 10.9 ± 6.7 mm Hg, respectively, as measured with the rebound tonometer and 12.2 ± 5.3 mm Hg, 15.7 ± 12.5 mm Hg, and 12.4 ± 5.4 mm Hg, respectively, as measured with the applanation tonometer. Measured IOP did not differ significantly between the 2 tonometers 3 hours before surgery and 2 hours after surgery, but measured IOP differed significantly between the tonometers 24 hours after surgery.
Conclusions and Clinical Relevance—Use of a rebound tonometer underestimated IOP, relative to results for use of an applanation tonometer, by 1.65 mm Hg in eyes 24 hours after phacoemulsification. Caution should be used when IOP measurements obtained with a rebound tonometer are in the high part of the reference range, and verification of these values with an applanation tonometer would be advised.
