The scale readings of Schiotz tonometer were compared to anterior chamber manometric recordings in normal and glaucomatous dog eyes. This in vivo studies compared the tonometer scale readings with 5.0, 7.5 and 10.0 weights to manometric pressures recorded from the anterior chamber in dogs under general anesthesia. The tonometric scale readings from both open and closed systems were compared to the actual manometric pressures.

There were no significant differences between the normal and glaucomatous eyes comparing the 5.5, 7.5 and 10 g weights in both the open and closed systems. Ocular rigidity for the normal canine eye at 10 to 20 mm Hg intraocular pressure was 0.0263. The dog has less displacement of aqueous humor than man when the Schiotz instrument is placed on the cornea with the 5.5 g, 7.5 g and 10 g weights.