Real-Time and Non-Invasive Monitoring of IOP in Glaucoma Patients

Abstract

Affecting approximately 3 million people in the United States, glaucoma is the leading cause of blindness that manifests due to elevated intraocular pressure (IOP) damaging the optic nerve. Early detection of glaucomatous ocular environments allows for improved prognosis of the disease in an effort to reduce the rate at which symptoms become prevalent. Since glaucoma is a chronic disease, there is a need for real-time, non-invasive IOP monitoring to provide physicians data of IOP fluctuations over time to make decisions with regards to further treatment interventions. Current IOP monitoring devices like the Goldmann Applanation Tonometer and the iCare tonometer are based on principles wherein the magnitude of the corneal stiffness translates to IOP. However, the mechanism employed is not only contact-based and causes discomfort to patients but also makes acquiring frequent measurement inaccessible. Furthermore, nocturnal IOP monitoring is necessary for physicians to gauge the extent of fluctuations which are elevated further by the supine position, however there are currently no FDA-approved devices focused on this need despite its significance.

Eye-D.E.A Labs has developed an ultrasound-based system that determines IOP by measuring the corneal stiffness using the rebound of the ultrasound waves due to acoustic impedance based on characteristic tissue properties. The device is intended for recording quantitative IOP measurements at designated time intervals to output an intermittent IOP pressure recording while also timely delivering the recorded information to the physician for review. Technical modeling conducted using COMSOL, MATLAB, and Python established magnitudes of thermal heat generation, acoustic force generation, and acoustic impedances of different system constructs. Future work will focus on integrating, testing, and validating all the abovementioned models to ensure sequential operation of each system. Benchtop experiments will also focus on modeling a conceptually, translatable proof-of-concept for overall feasibility and technical execution.

Video