Peripheral Pattern Electroretinography: System Upgrade, Novel Protocol Development, & Clinical Validation

Clinical motivation: Glaucoma is the second leading cause of blindness worldwide affecting more than 60 million people. It almost always begins silently and asymptomatically causes irreversible damage and apoptosis to the retinal ganglion cells (RGC). Unfortunately, there is no cure for glaucoma but with therapeutic interventions involving monitoring, medications, and/or surgery it is possible to halt and significantly slow down the progressive loss of vision. Early detection and diagnosis are key and the most quintessential steps to preserving vision that have been or can potentially be affected by glaucoma. Capability gap: The standard of care diagnostic tests for glaucoma, OCT imaging and visual field tests, target the central retina. A less-used functional test, pattern electroretinography (PERG), also evaluates the central retina and has been shown to be very sensitive in detecting early signs of dysfunction. However, it has been hypothesized that the earliest retinal damage in glaucoma begins, at least in some patients, in the peripheral retina. Solution: To address this, an initial peripheral-retina PERG (pPERG) system prototype was previously built. For earliest detection, it is crucial to be able to detect glaucomatous damage in localized regions of the retina, which is time consuming and therefore clinically impractical if done serially. To address this, this study rebuilt the initial pPERG prototype and created a novel protocol for evaluating three radial sectors of the peripheral retina simultaneously. The system was validated on 26 subjects including glaucoma suspects, early-stage patients and normally sighted individuals. In summary, the novel pPERG combined with the central PERG have the potential to be a comprehensive diagnostic tool for glaucoma.