A System for Measuring and Controlling Eye Pressure

Chris Passaglia, PhD
University of South Florida (Tampa, FL)
Year Awarded:
2014
Grant Duration:
July 1, 2014 to June 30, 2017
Disease:
Glaucoma
Award Amount:
$100,000
Grant Reference ID:
G2014105
Award Type:
Standard
Award Region:
US Southeastern

Recipient of the Thomas R. Lee Award for National Glaucoma Research.

Chris Passaglia, PhD

An Implantable System for Intraocular Pressure Measurement and Control

Summary

To understand the causes and effects of glaucoma, researchers often rely on animal models whose eye pressure is elevated by experimental means. Traditional methods of elevating pressure can reproduce key features of the disease, but they are limited by factors that are difficult to control, including finite success rates, sporadic pressure information, and variable exposure histories. These limitations hamper research progress and may prevent major breakthroughs. The aim of this project is to develop a wireless implantable device for continuous measurement of eye pressure. The device will be incorporated into a smart pump system that would for the first time give glaucoma researchers and clinicians unprecedented control over eye pressure level.

Details

Dr. Passaglia is engineering an implantable device that continuously records eye pressure and wirelessly sends the data to a remote computer for storage and analysis. The device is intended for use in rats and larger mammals, which could include humans. It will give researchers, and ultimately clinicians, a detailed log of eye pressure history, which is essential for interpreting the impact of pressure on the eye and its relationship to glaucoma, as well as (potentially) the impact of treatment.

To understand the causes and effects of glaucoma and devise new treatments, researchers often use animal models in which eye pressure is increased by genetic or experimental means. The onset and time course of pressure changes are usually monitored in these animals by taping a handheld tonometer to the cornea. This is a laborious effort that is rarely done more than once a day, which means that moment-to-moment fluctuations in eye pressure and the impact of those fluctuations on eye function go unnoticed. The frequency of pressure readings is even more sporadic in a clinical setting, raising questions about the possible role of unseen pressure spikes in the disease.

Dr. Passaglia’s lab aims to address these issues by developing a wireless eye pressure sensor that is implantable in rats, a popular animal model for glaucoma research. A prototype has been built that directly measures pressure via a fine cannula running from a sensor placed under the skin to the anterior chamber of the eye. The cannula remains in position for months on end without damaging internal tissues, even in the freely-moving eye. The broader goal is to translate the system to larger mammals, which could include humans. There is a great need for such a system because commercial pressure-measurement devices were not designed for the eye and thereby suffer from issues of implant size, signal drift, transmission range, and battery life.

Dr. Passaglia’s lab is using the system to characterize the variability of pressure in normal and glaucomatous rat eyes in order to evaluate the hypothesized role of pressure history in glaucoma. Once fully functional, the system will also be made available to interested researchers to help speed progress in the fight against this thief of sight.

About the Researcher

Christopher L. Passaglia is an associate professor of chemical & biomedical engineering at the University of South Florida, with an appointment in the Department of Ophthalmology. He received a PhD in bioengineering & neuroscience from Syracuse University and postdoctoral training in vision research at Northwestern University. His lab investigates how the eye communicates visual information to the brain and how normal information transmission is altered by glaucomatous processes. His work has garnered several honors, including the Lindsley Prize from the Society for Neuroscience, Smith Family New Investigator Award from the Medical Foundation, and CAREER award from the National Science Foundation. His current research projects are supported by this BrightFocus award and the National Eye Institute.
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