Three minutes of looking at red light once a week may help our eyesight, new research suggests. The findings show that red light might be a cheap and easy treatment for declines in color vision as we get older.

Last year, researchers from University College London did a study on red light therapy (疗法). 24 healthy volunteers, aged between 28 and 72, were asked to look at red light for three minutes every day for two weeks. Tests later found that the eyesight of people over the age of 40 improved.

To test the possible weak points of their therapy, they did a new study this year. Instead of using the light every day, they used it once a week. The new study included 20 volunteers, aged between 34 and 70, all with healthy vision. Some received red light therapy in the morning, and others received it in the afternoon. They were then tested on their color vision up to a week later.

On the whole, those who got the treatment in the morning showed a 17% improvement in their color vision, even a week later. Those who got the treatment in the afternoon did not have any improvement.

"We've found that one single exposure (暴露) to red light in the morning can greatly improve declining vision," said lead author Glen Jeffrey.

The findings do support their earlier work, and they might make the treatment more practicable, since a once-weekly treatment is easier to stick to than a daily one. But the team's promising results are still drawn on small numbers of healthy volunteers. Larger studies would be needed to show the benefits of red light therapy.

"In the near future, a once-a-week three-minute exposure to deep red light could be done while making a coffee or listening to a song, and such a simple thing could change eye care and vision around the world," Jeffrey said.

Given its low cost (as little as $15) per device, and simplicity, the team is excited about the future of their therapy.