DIFFERENTIAL VISUAL LATENCY IN GLAUCOMA
Glaucoma, a leading cause of visual disability and blindness, is often diagnosed and treated only after significant neuronal damage has occurred. Our laboratory investigates psychophysical procedures that could potentially lead to earlier diagnosis and interventions. We are currently assessing visual latency at various retinal loci to determine the effectiveness of differential latency (DL) as a diagnostic tool
PSYCHOPHYSICAL INVESTIGATIONS OF PARALLEL PATHWAYS
The neurons that constitute the two primary retinocortical pathways - the parvocellular (PC) and magnocellular pathways (MC) -- code different features of the visual world. While neurons in the PC pathway are color-opponent and most sensitive to small, slowly moving stimuli, neurons in the MC pathway are non-color opponent and most sensitive to large, rapidly moving stimuli. A goal of my research is to devise psychophysical strategies that allow the isolation of the PC and MC pathways in human subjects. Such strategies may lead to a better understanding of the functional significance of the pathways. A long-term goal of this research is to develop clinical tests that aid in the diagnosis of diseases that may affect one of the pathways to a greater extent that the fellow pathway. Recent experiments have utilized visual latency, masking, and spectral sensitivity paradigms to reveal the distinctive operational properties of the PC and MC pathways. We have found that, compared to the PC pathway, the MC pathway detects stimuli with a shorter latency, is more vulnerable to forward and backward masking, and is less profoundly altered in red-green dichromacy.
We are also interested in further characterizing the ON and OFF pathways in the primate visual system. Current literature on the independence of these channels contains conflicting data. Psychophysical masking studies will be used to study these channels in human subjects.
COGNITIVE THERAPY TO IMPROVE PATIENT ADHERENCE WITH DRUG REGIMENS
Compliance failure in the medical treatment of glaucoma is well documented and has received much recent attention. While patient education and strict monitoring of compliance are important tools, they may not reach their full potential absent a more comprehensive consideration of the patient’s cognitive state. The interplay between the patient’s beliefs (rational and irrational) with his emotional state and behavior are key elements missing from current approaches. I am interested in developing cognitive psychotherapy interventions that improve patient medication compliance.