A Korean research team developed smart contact lenses that stimulate the brain through the eyes and found effects similar to antidepressants in a mouse experiment.
A team led by Park Jang-ung, a professor in the Department of Materials Science and Engineering at Yonsei University, developed soft, transparent smart contact lenses that can stimulate brain regions associated with depression. The findings were published on the 15th in the international journal "Cell Reports Physical Science."
The retina is not just an organ that receives light; anatomically, it is neural tissue consolidated with the brain. Signals entering through the retina travel along the optic nerve to the brain. The team noted that by using this pathway, it could stimulate brain circuits related to mood regulation without opening the head or implanting devices in the brain.
The lenses apply an electrical stimulation method called "temporal interference." It sends two weak electrical signals from ultrathin electrodes in the lens so that stimulation intensifies only at the point where the two signals meet. The team said, "It is similar to how a bright spot appears where the light from two flashlights overlaps," adding, "The electrodes are on the eye surface, but the actual stimulation is designed to occur precisely deep in the retina."
The team conducted experiments on mice induced to show depressive symptoms. The mice were divided into groups that received no treatment, electrical stimulation from the contact lenses, and fluoxetine, an antidepressant ingredient. Fluoxetine is the main ingredient in the well-known antidepressant "Prozac," and helps serotonin, a neurotransmitter related to mood regulation, act longer in the brain.
In the results, mice that received contact lens stimulation for 30 minutes a day over three weeks showed reduced depressive symptoms in behavior, brain activity, and biomarkers. The behavioral improvement was similar to that of mice given fluoxetine. In addition, consolidation between the hippocampus and prefrontal cortex, which had weakened due to depression, was restored. The hippocampus is important for memory and emotion regulation, and the prefrontal cortex is important for judgment and emotion regulation. When consolidation between the two regions collapses, brain circuits related to depressive symptoms can be disrupted.
Mice treated with the contact lenses showed reduced inflammation-related substances in the brain, and blood levels of corticosterone, a stress hormone, decreased by 48% compared to untreated depression model mice. Conversely, serotonin increased by 47%.
The team said, "Smart contact lenses have mainly been studied for diagnosis and monitoring, such as measuring intraocular pressure or blood glucose," adding, "This is the first case of using contact lenses to treat a brain disorder, as in this study."
However, this technology will not be used in people right away. Park said, "As a new medical technology, it must undergo rigorous clinical evaluation in patients before it reaches the market," adding, "We plan to develop fully wireless lenses, test long-term safety in larger animals, and then develop user-specific stimulation technology to conduct clinical trials in patients."
References
Cell Reports Physical Science (2026), DOI: https://doi.org/10.1016/j.xcrp.2026.103303