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A Weekly Dose of Red Light Might Improve Aging Eyesight, Study Finds

People given the low-cost therapy in the morning performed noticeably better on tests of their color vision.

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A red traffic light in Moscow, Russia.
A red traffic light in Moscow, Russia.
Photo: Alexander Nemenow/AFP (Getty Images)

Three minutes of staring into a red light once a week may help our eyesight as we get older, new research this week suggests. Researchers in the UK found that volunteers given a weekly session with red light in the morning performed better on tests of their color vision. The findings are the latest to indicate that red light might be a cheap and easily accessible treatment for age-related declines in color vision.

Last year, researchers from University College London published the results of a small human trial involving red light therapy. Healthy volunteers were asked to stare at a red light “torch” using their dominant eye for three minutes every day for two weeks. Tests afterwards found that people over the age of 40 improved on tests meant to measure how well they could see contrast between colors—a function of the retina’s cones. Lead author Glen Jeffery told Gizmodo at the time that the findings provided a proof-of-concept for their theory.


Mitochondria are the part of the cell that produces most of its energy. But as we age, the retina’s mitochondria begin to break down faster than elsewhere, which is thought to contribute to the decline of our retina, particularly our cones, and the gradual loss of our ability to see color. “However, mitochondria absorb some forms of light, including deep red, and this recharges the battery, improving cell function—this works well in the retina because they have so many mitochondria. Hence we use this to improve vision,” explained Jeffrey.

This new research of theirs wanted to test the possible limitations of their therapy. Instead of using the light every day, they scaled it back to once a week. And they opted for a lower-energy light as well. The same wavelength of deep red light (670 nanometers) was used. The study involved 24 people between the ages of 34 and 70, all with healthy vision. Most who received the therapy were given it in the morning. Some also received it in the afternoon as part of a later experiment, and others acted as a control group. They were then evaluated on their color vision, based on tests of distinguishing color contrast, up to a week later.


Overall, those who got the treatment in the morning showed a 17% improvement in their color vision on average, even a week later. Those who got the treatment in the afternoon did not have any improvement, likely due to changes in how mitochondria reacts to light over the course of the day that the team’s past research has documented. The new study’s findings are published in Scientific Reports.

“We demonstrate that one single exposure to long wave deep red light in the morning can significantly improve declining vision, which is a major health and wellbeing issue, affecting millions of people globally,” said Jeffrey in a statement from the University College London.

The findings do support their earlier work, and they might improve the practicability of the treatment, since a once-weekly staring session is easier to stick to than a daily regimen. But the team’s promising results are still based on very small sample sizes of healthy volunteers. Larger trials would be needed to confirm any benefits of red light therapy.

Even the authors acknowledge that there are still many questions left to be answered. Some of their volunteers, for instance, had a significantly greater response to the treatment than others, even among those similarly aged, suggesting that there might be unique factors that predict how well the therapy works for any one person.


“In the near future, a once a week three-minute exposure to deep red light could be done while making a coffee, or on the commute listening to a podcast, and such a simple addition could transform eye care and vision around the world,” Jeffrey said in the University College London release.

Given its low cost (as little as $15 per device, Jeffrey previously told Gizmodo) and simplicity though, the team is excited about the potential of their therapy, should the research continue to pan out.