A window to the brain? eye signals may track dopamine

This study explores whether electrical signals from the eye and brain can serve as a noninvasive marker of dopamine activity. About 50 adults—half with Parkinson's disease and half without—will have their eye and brain responses measured using sensors on the skin. People with Parkinson's will be tested before and after taking their usual medication, while healthy volunteers will receive a single dose of levodopa/carbidopa eye drops in one eye and a placebo in the other. The goal is to see if blue-light responses change with dopamine levels, which could lead to a simpler way to monitor conditions like Parkinson's.