Christopher L. PassagliaSpeaker
Christopher L. Passaglia, PhD
Associate Professor of Chemical and Biomedical Engineering, University of South Florida College of Engineering
Title: Continuous measurement and control of intraocular pressure in normal and glaucomatous eyes
Abstract: In order to gain insight into the pathophysiology of glaucoma researchers use animal models in which intraocular pressure (IOP) is elevated by experimental means. While much has been learned from animal models about the effects of ocular hypertension on the eye, research progress remains hampered by issues of high failure rates, sporadic IOP data, and variable IOP exposure histories. My lab has developed new tools that can overcome these longstanding limitations. One is a wireless battery less sensor that measures IOP round-the-clock with 0.2mmHg resolution, which we have used on awake freely-moving rats for weeks to months. Results are presented that show IOP varies dynamically in normal rats by several mmHg over multiple time scales. A second is a smart pump that automatically sets and holds IOP at any level desired by the user, which we have used to examine ocular fluid dynamics in anesthetized animals. Measurements of aqueous humor formation rate, episcleral venous pressure, conventional outflow facility, and unconventional outflow facility are presented for normal rats. And, a third is a tethered ocular perfusion system, which we have used to chronically and reversibly alter IOP. Results are presented that show high IOP can cause glaucomatous cell death without damaging aqueous outflow pathways of the eye or changing their biomechanical properties. Together, these one-of-a-kind tools offer glaucoma researchers unprecedented knowledge and control of IOP in rats and potentially larger animals, promising to help speed progress in the fight against this visually- debilitating disease.