An insightful new technology has been developed for treating depression.

While millions of adults in the US use antidepressants like Prozac, the side effects — like weight gain or sexual dysfunction — can make the medications an uncomfortable option.

However, a new, drug-free treatment delivered eye-opening results that were as effective as one of the most commonly prescribed pills.

Selective serotonin reuptake inhibitors (SSRIs) like Prozac block the brain from absorbing serotonin to stabilize mood, but can also dull emotions and result in difficult withdrawal symptoms for some.

This prompted researchers to develop a less invasive method involving transparent contact lenses that used built-in electrodes to deliver mild electrical signals to brain regions associated with depression and mood.

This particular treatment showed improvements in mood and behavior comparable to Prozac when used on mice for 30 minutes per day for three weeks.

The findings, written up in the journal Cell Reports Physical Science, looked at a method called temporal interference to stimulate the brain.

This delivers two electrical signals to the retina that only become active when they intersect deep inside the eye, meaning the treatment only targets specific regions of the brain.

Senior author Jang-Ung Park of Yonsei University compared this to two flashlights.

“Each beam alone is dim, but where they overlap, a bright spot appears, and that bright spot can be created far away from the flashlights themselves,” Park said in a press release. “Our contact lens does the same with two harmless electrical signals.”

In order for the lenses to be transparent and flexible, the team built electrodes from ultrathin layers of platinum and gallium oxide (a material with electrical conductivity).

The lenses were then tested between four groups of mice: those receiving temporal interference, those getting fluoxetine (the active ingredient in Prozac), depressed mice who received no treatment and a non-depressed control group.

All signs of depression measured by behavior, electrophysiological brain recordings and blood and brain biomarkers were reduced with the contact lenses.

In particular, the treatment reduced levels of inflammatory molecules in the brain, lowered blood corticosterone (equivalent to cortisol in humans) by 48% and increased serotonin by 47%.

Connectivity between the hippocampus and prefrontal cortex, which is lost due to depression, was also restored, as seen in recordings of brain activity.

The lenses were so effective that a machine learning model asked to group the mice based on their behavior, brain activity and biomarker levels consistently grouped the contact lens treatment group with the non-depressed control mice group.

The next step for the team is to take the technology through rigorous testing and evaluations, as well as modifications to adapt the treatment for humans.

“Next, we plan to make the lens fully wireless, test it for long-term safety in larger animals and personalize the stimulation for each user before advancing into clinical trials in patients,” said Park.

And researchers hope the innovative method can be applied to multiple conditions.

“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,” Park said.