Researchers at Yonsei University have developed an innovative type of smart contact lens that can stimulate the brain and significantly reduce depressive symptoms in mice. The findings suggest the technology may be as effective as fluoxetine, the active ingredient in Prozac.
The soft, transparent lenses contain embedded electrodes that deliver mild electrical signals through the retina to targeted brain regions associated with mood regulation. According to senior author Jang-Ung Park, this approach opens “an entirely new frontier” for treating brain disorders via a non-invasive route.
Temporal interference
The contact lenses use a technique known as temporal interference stimulation. This method involves transmitting two low-intensity electrical signals that only become effective at the point where they intersect. This allows for precise targeting of specific brain circuits without directly implanting devices into the brain.
Park compares the concept to overlapping beams of light: individually weak, but powerful at the point of convergence. In this case, the intersection occurs at the retina, triggering neural pathways that connect to mood-related brain regions.
The lenses are constructed from ultrathin layers of materials such as gallium oxide and platinum, ensuring flexibility and transparency. While earlier generations of smart lenses focused on monitoring, such as measuring intraocular pressure or glucose levelsm this marks the first application aimed at actively treating a neurological condition. The research was recently published in Cell Reports Physical Science.
Promising results
The research team tested the technology in four groups of mice: healthy controls, untreated depressed mice, depressed mice receiving the lens-based stimulation, and depressed mice treated with fluoxetine.
After three weeks of daily 30-minute sessions, the mice treated with contact lenses showed marked improvements. Behavioral tests, electrophysiological recordings, and biomarker analyses all indicated reduced signs of depression. Notably, the improvements were comparable to those observed in the medication group.
Brain recordings revealed restored connectivity between the hippocampus and prefrontal cortex, regions critical for emotional processing. In addition, biological markers improved: inflammatory molecules in the brain decreased, corticosterone levels dropped by nearly 50 percent, and serotonin levels increased significantly.
Findings validated
To further validate the results, the researchers applied a machine learning model that classified the mice based on behavioral, neural, and biological data. The model consistently grouped the contact lens–treated mice with healthy controls rather than with untreated depressed mice.
This convergence across multiple data domains strengthens the case for the technology. As Park notes, the alignment of behavioral, neurological, and biochemical improvements is particularly compelling and underscores the therapeutic potential of this approach.
Not there yet
Despite the promising findings, the researchers caution that significant work remains before the technology can be tested in humans. Future steps include developing a fully wireless version of the lens, conducting long-term safety studies in larger animal models, and tailoring stimulation protocols to individual users.
If successful, this innovation could represent a major shift in the treatment of depression and other neurological conditions, including anxiety and addiction. For the ICT&health sector, it highlights the growing role of advanced wearables that not only monitor health but also deliver targeted therapies, potentially transforming how brain disorders are treated.
Earlier this year, Japanese researchers developed a smart contact lens with an integrated thin-film sensor that can measure eye pressure in real time during daily use. They integrated an extremely thin, flexible sensor directly into a soft contact lens. This creates a measurement solution that is not only wearable, but also suitable for continuous (24/7) monitoring without compromising the wearer's comfort.
