Contact Lenses Deliver Electrical Signals to Treat Depression in Mice

A study published in Cell Reports Physical Science tested transparent contact lenses equipped with electrodes that deliver mild electrical signals to brain regions linked to mood. The method uses temporal interference, sending two electrical signals through the retina that intersect only at targeted deep brain areas.

Senior author Jang-Ung Park of Yonsei University said the approach is similar to two flashlights whose beams overlap to create a bright spot far from the source. Researchers compared four groups of mice: those receiving the lens treatment, those given fluoxetine, untreated depressed mice, and a non-depressed control group.

All measured signs of depression, including behavior, brain recordings, and biomarkers, decreased in the contact-lens group.

The lenses reduced inflammatory molecules in the brain, lowered blood corticosterone levels by 48 percent, and raised serotonin levels by 47 percent. Brain connectivity between the hippocampus and prefrontal cortex, which depression disrupts, was restored according to electrophysiological recordings.

A machine learning model grouped the contact-lens mice with the non-depressed control group based on behavior, brain activity, and biomarker data.

Park said the team plans to make the lenses fully wireless, test long-term safety in larger animals, and personalize stimulation before moving to human clinical trials. Researchers also stated the approach could be applied to anxiety, drug addiction, and cognitive decline.