Scientists have developed brain-stimulating contact lenses (CLs) that produced antidepressant-like effects comparable to fluoxetine (Prozac) in a mouse model of depression, according to a study published in Cell Reports Physical Science.
Researchers used CLs with in-built electrodes to deliver mild electrical signals to the retina, activating neural pathways connected to brain regions associated with depression. After three weeks of CL treatment, mice treated with corticosterone to induce depression-like behaviour displayed reduced behavioural, neural and physiological signs of depression.
“Our work opens up an entirely new frontier of treating brain disorders through the eye,” said senior author and materials scientist Professor Jang-Ung Park of Yonsei University in Seoul. “We believe this wearable, drug-free approach holds tremendous promise for transforming how depression and other brain conditions are treated, including anxiety, drug addiction and cognitive decline.”
Current depression treatments – including drugs, electroconvulsive therapy and brain implants – work by targeting brain regions and circuits associated with mood. Since the retina connects to some of these regions, the researchers wanted to try using the eye as a pathway to stimulate the brain. Previously designed smart CLs have been developed to monitor ocular and metabolic disorders – by measuring intraocular pressure or glucose levels, for example – but this is the first reported use of CLs to treat a brain disorder, Prof Park said.
The CLs use a method called temporal interference, in which two high-frequency electrical signals delivered to the retina overlap to produce a lower-frequency interference pattern. This stimulates retinal neurons and downstream pathways connected to mood-related brain regions.
