Ultra-Sonic Non-Contact Tonometer in Glaucoma-IOP Checks

Eye Star Corporation, Bryn Mawr PA

Investigators

Abstract

DESCRIPTION (provided by applicant): The wide availability of blood pressure measuring devices, particularly its availability for self use by patients, has revolutionized the effectiveness of medical diagnosis and treatment of systemic hypertension over the past decade, as experienced personally or through loved ones. The ultimate goal here is to achieve a similar level of care in the diagnosis and treatment of ocular hypertension as it relates to glaucoma, one of the major causes of blindness and visual disability in the United States and the World. To achieve this, the Phase I step is to develop a working laboratory model of an Ultra-Sonic Non-Contact Tonometer (USNCT) to measure the intra-ocular pressure (IOP) in a model eye. The patented operating principles of the USNCT are based on physics not heretofore utilized in any known glaucoma related tonometers. The USNCT achieves its IOP measurement by detecting a small deformation of the cornea caused by an ultrasonic beam of known intensity impinging on it from air by tracking the resultant phase shift in the reflected beam. It is a primary Phase I goal to demonstrate that this is possible with ultrasonic intensities currently accepted as clinically safe by the FDA. In case of successful completion of Phase I, Phase II of the project will progress to USNCT measurements of freshly enucleated cadaver eyes with IOP controlled by intracameral manometry. Absolute calibration with known IOP will thus be possible; relative comparisons to some other tonometers will also be possible. The final goal of Phase II is the design and manufacture of a working prototype that can be approved by the FDA for trials on human subjects. The USNCT holds the promise of the following specific advantages: a) Painless, b) Startle free, c) Requires no topical anesthetic eye drops, d) Independent of small patient movements (e.g., breathing, tremors, poor head alignment, etc.). e) Independent of small corneal epithelial surface irregularities, f) Allows self-measurement by patient, g) Expected accuracy comparable to current state of the art tonometers. Phase I of the project will end with a working model of the USNCT that demonstrates the feasibility of the method in a model eye with IOP controlled by intracameral manometry.