Researchers find electrical brain stimulation can improve vision

Stimulation of the visual cortex of the brain for 20 minutes with a mild electrical current can improve vision for about two hours, and those with worse vision improve the most, according to a Vanderbilt University study.  

Twenty young, healthy subjects with normal or near-normal vision were asked to evaluate the relative position of two identical vertical lines and judged whether they were perfectly aligned or offset — a test more sensitive than a standard eye chart. The researchers then passed a very mild electrical current through the area at the back of the brain that processes visual information. After 20 minutes, the subjects were asked to perform the test again, and about 75% showed measurable improvement after the brain stimulation.

Geoff Woodman, associate professor of psychology, noted, “This kind of stimulation can improve cognitive processing in other brain areas, so if we stimulate the visual system, could we improve processing? Could we make someone’s vision better — not at the level of the eye, like Lasik, but directly at the level of the brain?”

Geoff Woodman, associate professor of psychology at Vanderbilt University.

The study also measured how the stimulus changed the speed at which the brain processed visual information and whether the stimulation improved contrast sensitivity. In the contrast experiment, they found that the stimulation only improved contrast sensitivity at frequencies also associated with visual acuity.  

Lead author Robert Reinhart, an incoming assistant professor in the Department of Psychological and Brain Sciences at Boston University who conducted this research as a Ph.D. student at Vanderbilt, noted a major variation between subjects. “We saw that those who came in with poorer vision, who might be on their way to needing glasses, had rather big leaps, while others who came in with excellent vision showed no change.”

A report of the study has been published in Current Biology .