Cataract remains the primary cause of blindness in the world today. The ability to detect a pre-cataractous lens would allow those at risk to modify environmental risk factors, such as sunlight exposure, cigarette smoking, diabetes control, and alcohol consumption, to avoid or prolong the need for surgery. Early detection would also be helpful in identifying patients for clinical trials evaluating drugs to prevent cataract formation. However, until now, the only way to detect alpha crystallin levels and protein aggregation in the pre-cataractous eye was to remove the lens and perform chemical analysis.
Dr. Manuel Datiles of the National Eye Institute (NEI) from the National Institutes of Health and Dr. Rafat Ansari of the National Aeronautics and Space Administration (NASA)-Glenn in Ohio collaborated to develop a diagnostic tool using dynamic light scattering (DLS) technology used in the Space Station to non-invasively detect pre-cataractous changes in the lens. Nuclear senile, or age-related cataract, the most common type of cataract, results from damage to lens proteins through oxidative stress. Over time, the damaged lens proteins aggregate, causing the lens to cloud. In the last few years, NEI investigators have shown that the molecular chaperone, alpha crystallin, prevents lens proteins from aggregating. Specifically, alpha crystallin binds to the unraveled tips of damaged lens proteins. The bound proteins cannot then stick to one another, thus preventing protein aggregation and cataract formation. Humans are born with a fixed amount of alpha crystallin. Cataracts begin to form as the supply of alpha crystallin is exhausted.
The DLS device measures the amount of unbound alpha crystallin in the lens to monitor lens health and cataract risk. The development of this device now makes it possible to monitor pre-cataractous changes in the lens to identify at-risk patients and test new anti cataract drugs. In addition, oxidative stress (which cause the loss of alpha crystallin protein) is believed to cause aging and related ilnesses as well as radiation injury. Hence, Drs. Datiles and Ansari are collaborating with Dr. Walter Stark of Johns Hopkins Hospital and NASA physician-scientists to use the DLS to study aging related cataract and related illnesses like Alzheimer’s disease, as well as radiation injury in astronauts.
Manuel Datiles, National Institutes of Health
Rafat Ansari, National Aeronautics and Space Administration
J. Samuel Zigler, John Hopkins University
Frederic Ferris, National Institutes of Health
JAMA Ophthalmology Publication