Red light therapy: eyesight may improve after exposure to dark red or near infrared light

Exposure to dark red or near infrared light can improve the function of the mitochondria in the eye, the powerhouses of cells, resulting in a slight but lasting improvement in vision loss.

Through Claire Wilson

An unusual experimental treatment for discolored vision involves shining red light into the eyes for a few minutes to stimulate activity in mitochondria, microscopic structures that provide energy inside cells.

In the approach’s first small test on 24 people, short exposure to light slightly improved people’s performance in color vision tests for several days.

Dark red light and near infrared light have previously been shown to improve mitochondria function in a range of cell and animal experiments. These wavelengths appear to work by improving the performance of key molecular structures within mitochondria, called ATP synthase pumps.

These pumps manufacture a molecule called ATP, which cells use for energy, rotating in the aqueous environment of the mitochondria. Dark red light has just the right wavelength, at 670 nanometers, to be absorbed by water molecules, giving them more energy.

This makes the water surrounding each pump less viscous, allowing the structure to spin faster. “It’s like heating jam to make it easier to mix,” says Glen Jeffery of University College London.

While making cells more energy efficient can affect a wide range of bodily systems, Jeffery’s group studied cells in the retina, a light-sensitive piece of tissue on the back of the body. eyebecause they contain more mitochondria than any other cell in the body. Altered mitochondria can contribute to reduced eyesight with age and have been implicated in several causes of blindness.

Previous work in flies suggested that the mitochondria produce most of the ATP in the morning. Jeffery’s group therefore conducted a trial of exposure to red light in people between the ages of 37 and 70, comparing the morning treatment to that in the afternoon, as a control group.

The participants had a dim dark red light on their eyes for 3 minutes. Three hours later, their color vision was tested by asking them to try to detect letters appearing against a background of a similar color. The team focused on color vision because the cells in the retina responsible for black and white vision tend to die with age.

When people received treatment, between 8 a.m. and 9 a.m., their performance on the color contrast test improved 12 to 17% from before treatment. Ten members of the group were also tested a week later and their results were still up to 10% better. But there was no significant change if the treatment was done in the afternoon.

Some people have said they haven’t noticed any improvement in their vision despite better test results, says Jeffery.

Louise Gow at the British Charity The Royal National Institute for the Blind says the results are exciting, but more study is needed to see if the approach can bring any notable benefits to people’s eyesight. “A larger study would establish the evidence for this type of innovative treatment,” she said.

Other groups have found that treatment with red light may be beneficial for people with a common cause of blindness called Macular degeneration and the aggravation eyesight caused by diabetes.

Treatment can help in a variety of conditions, as strengthening mitochondria “activates all the systems in the cell that make the cell work better,” explains Janis Eells at the University of Wisconsin-Milwaukee. Eells works with a company called LumiThéra, which markets a red light device to treat macular degeneration in some countries.

Various groups have also shown that shining a dark red or near infrared light on the head can be beneficial for animals with induced brain injuries and conditions, such as stroke and Parkinson’s disease, in laboratory experiments.

Jeffery’s group also found that irradiation with red light can protect the bees exposed to neonicotinoid insecticides, which damage the mitochondria. The group offers beekeepers to put lamps in their hives.

Journal reference: Scientific reports, DOI: 10.1038 / s41598-021-02311-1

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