The visual signal travels from the eye to the brain along retinal ganglion cell (RGC) axons, and the anatomy and physiology of these retinal output neurons are the focus of research in my lab. A small group of RGCs in the inner mammalian retina express the photopigment melanopsin and can respond directly to light. These neurons provide information regarding environmental light levels (irradiance) to the brain centers that regulate circadian rhythms (daily rhythms of physiology and behavior) and the size of the pupil of the eye. The mechanisms underlying the intrinsic light responses of these cells have yet to be fully elucidated, and we are currently investigating how these photoreceptors are able to convert captured light photons into an electrical signal.

 

In addition, we are evaluating the contribution of melanopsin-containing RGCs to light-evoked pupil constriction and we are conducting clinical studies that examine the effect of conditions such as glaucoma and traumatic brain injury on RGC photoreception.