Despite the medical advancement in the past decades, cataract remains the primary cause of blindness in the world, affecting more than 90 million people. Cataracts are formed when a protein, known as calpain, clouds the eye lens and impairs vision. The calpain protein is activated by triggers, including aging, diseases, injury, smoking, drinking, sunlight exposure, and long-term use of some medications. In the recent years, researchers have identified various types of effective calpain inhibitors. If cataract is found early, the inhibitors could delay the need for surgery for years, even to the point where people may never need surgery. The prospect of developing pharmaceuticals needs very early detection of the cataract.
Ying-Ling Ann Chen, research assistant professor of physics at the University of Tennessee Knoxville based at the Space Institute in Tullahoma, works in the Center for Laser Applications (CLA) and was awarded the Swift Info Technology contract to perform the investigation of a method of detecting early-stage cataract. The technique will employ P3 and P4 Purkinje images (the 3rd and 4th reflection from interior ocular surfaces) to quantify cataract development stage and use optical eye modeling to assist the optical design. To provide adequate predictions, fractal particle models will be used as the computational approach.
Previously, CLA studies have used fractal model to describe sub-micron particle growth. This complexity of the particle model resulted in realistic predictions of the particulate growth. This is essential to develop radiation scattering and absorption methods to study particulate growth. This investment of effort is even more important to obtain accurate early-stage cataract characterization.
The design of the laboratory measurements will be initiated and the laser sources and detectors of CLA will be used to demonstrate or determine optimal radiation properties for early cataract detection using the P3/P4 ratio. The CLA radiation sources will be primarily a pulsed nitrogen laser that excites or pumps broadband dye lasers. Measurements of the P3/P4 ratios will be performed using a simulated ocular chamber. The design will enable optical absorption and scattering measurements to be performed over the wavelength range of visible to near-infrared to allow comparison with the computational predictions, and therefore, to determine the optimal properties of radiation for characterization of the early-stage cataracts.
After the laboratory testing, human eye testing will be performed in the last quarter of the 27-month project.