Pattern Electroretinograpy in Peripheral Retina: System Development and Validation in Human Subjects

Glaucoma, a family of disease defined by retinal ganglion cell loss, is the leading cause of blindness in the US. Early detection allows for a more favorable prognosis by allowing earlier management of the disease, thereby stopping or slowing progressive vision loss. Glaucoma is currently diagnosed through a combination of structural (optical coherence tomography, OCT), and functional (perimetry, pattern electroretinography) tests. These clinically available tests are limited to the central visual field, 20-30 degrees (full angles). Several studies [Bach et al. 1998; Hood et al. 2005; Ventura et al. 2006; Sehi et al. 2009; Banitt et al. 2013; Bach et al. 1992] demonstrate that the loss of peripheral ganglion cell function (beyond 30 degrees of visual angle) likely precedes functional loss in the central retina, at least in some patients. It can therefore be hypothesized that a stimulus designed to target ganglion cell function in the periphery will be more sensitive to early onset of glaucoma. To test this, a novel three- dimensional pattern stimulus system was designed and prototyped. Stimulus parameters were explored, and the system was validated in healthy subjects resulting in an initial normative database. Sensitivity of the test to glaucomatous damage was assessed. To make the system clinic friendly, the system software, user-interface and testing protocols were optimized.