The objective of this project is to develop a novel optical-based pressure sensor that allows for monitoring of intraocular pressure (IOP) on a frequent or continuous basis. Elevated IOP continues to be the primary risk factor for glaucoma due to its association with optic nerve damage and irreversible blindness. For approximately 60 million people worldwide suffering from this disease, careful monitoring and lowering of eye pressure are essential to mitigating further loss of vision and optic nerve deterioration. Current standard care, which involves routine IOP measurements during office visits, can only provide snapshots of the patient's IOP profile. Such infrequent measurements are inadequate to fully represent and characterize the patterns of the disease. In order to improve glaucoma care and determine the effectiveness of therapeutic treatments, there is a need for continuous and reliable IOP data to better understand the relationship between elevated eye pressure and optic nerve damage. Overall, the investigated technology will allow physicians to optimize and personalize treatment plans for patients and provide researchers with improved understanding of the natural history of glaucoma.
The scope of the project involves designing a sensor for direct measurement of intraocular pressure on a regular or continuous basis. The implantable device being developed utilizes changes in light reflectance to sense pressure. A camera is used to capture the sensor response to pressure variations and the obtained images can then be analyzed to determine the pressure profile using image-processing algorithms. A direct correlation between the sensor's optical appearance and applied pressure has been observed in preliminary benchtop results. Resolution of the pressure reading as low as 1 mmHg has been obtained from initial experimentation in a simulated pressure environment. With improved material selection for sensor components, it is likely that the sensitivity of the sensor will continue to increase as the design is optimized. The specific goals of the project include: (1) miniaturization of the sensor to sub-millimeter size using MEMS (microelectromechanical systems) fabrication, (2) evaluation of sensor performance in ex-vivo models and (3) development of image-processing algorithms. These goals involve an iterative design approach to optimize the sensor design parameters and validate reliability, fabrication methods and results through rigorous testing. Ultimately, with the ability to capture IOP fluctuations, the technology developed in this project will contribute to advancements in the diagnosis and treatment of glaucoma.
