Calibration of Non-invasive Tonometer for Mice Eyes

Abstract

Abstract: : Purpose: There is yet no satisfactory animal model of glaucoma. Mouse eye possibly represents the best mammalian model of glaucoma as it has many structural similarities to the human eyes such as trabecular meshwork, Schlemn’s canal, ciliary body, and retina. Availability of transgenic technology, relatively short life-span, and low cost also afford vast potential for research into the genetics of glaucoma. Currently no satisfactory method exists to measure intraocular pressure of mouse eyes non-invasively. Methods: Schiotz-like indentation tonometer was developed specifically to measure intraocular pressure of mouse eyes. Tonometer was calibrated using enucleated mouse eyes connected to a pressure transducer via a 30-gauge needle. Tonometer was then used to measure intraocular pressure in live mice. Results: Logarithmic regression line correlating the excursion of the indentation tonometer against the invasively measured intraocular pressure was plotted (R² = 0.7256) to calibrate the tonometer. Intraocular pressures of live mice were then measured non-invasively using the tonometer. Conclusions: We present a new non-invasive method of measuring mouse intraocular pressure. Using the regression curve, intraocular pressure can be derived from the excursion of an indentation tonometer specially designed for mouse eyes.

Keywords: intraocular pressure • animal model