Noninvasive Intraocular Pressure Measurement in Animals Models of Glaucoma

Abstract

Intraocular pressure (IOP) elevation is a critical risk factor for development and progression of glaucoma. As such, measuring IOP in animal models of the disease is important for any research work trying to understand the pathophysiologic mechanisms of glaucoma. Noninvasive IOP measurement in animals uses methods that have been adapted from use on humans. Calibration of the instruments used for the specific animal and even strain used is critically important for allowing meaningful comparisons of results. We describe below the methods used for noninvasive IOP measurement in animals that are relevant to glaucoma research.

Keywords: Applanation tonometry; Electronic tonometry; Glaucoma; Intraocular pressure; Methods; Model; Pneumotonometry; Rebound tonometry.

Figure 1

Schematic setup for tonometer calibration. A similar setup can be used for direct IOP measurement. Two 3-way valves are used: 3-way valve 1 has one port permanently closed and allows at will connection between the column of fluid and the eye. 3-way valve 2 allows replenishment of the fluid in the system using a syringe. The port connecting to the syringe is closed during measurements. Pressure transducer is optional if the open stopcock method is used. Components and eye are not to scale.