Functional in vivo imaging of single retinal ganglion cells in experimental glaucoma

Glaucoma is an age-related optic neuropathy affecting over 75 million people worldwide, resulting in unacceptable amounts of visual disability and blindness. In Canada, glaucoma care costs over $0.5 billion annually, posing a formidable social and economic burden. Current resources will be hopelessly inadequate to cope with the exponential growth in new cases as our population ages. We need creative and effective approaches to diagnose the disease more accurately and efficiently so that ophthalmologists can make early treatment interventions to reduce the chances of visual disability and blindness. While ophthalmologists use modern imaging to diagnose and monitor glaucoma, they cannot measure loss of retinal ganglion cells (RGCs, the special cells responsible for sending messages from eye to brain) lost in the disease. Instead, at best, they obtain crude macroscopic surrogates of RGC capacity. This project is on imaging how well individual RGCs function. We will use an imaging technique called two-photon ophthalmoscopy to image RGCs in a living mouse. We will study the impact of experimental glaucoma over time and determine how the signals we detect in the living mouse correlate with biological signs of RGC health. The research will give us a better insight into the disease process, and how age and eye pressure, the most important risk factors for glaucoma, affect the fate of RGCs. The translation potential of the project includes identifying therapeutic windows that could rescue RGCs, testing new drugs and establishing the foundation for using this technology clinically.