Red energy supplier: Just three minutes of deep red light in the morning can strengthen the eyesight that declines with age, as a pilot study suggests. A single light shower was sufficient to improve the test subjects’ color contrast vision by 17 percent – and the effect lasted for around a week. The reason for this: The red light stimulates the tired mitochondria in the retina to produce more energy in the form of ATP again.
From around the age of 40, the photoreceptor cells in our retina begin to age and tire: their mitochondria provide less and less energy in the form of the ATP molecule, and as a result our eyesight deteriorates. However, some time ago animal experiments showed that this fatigue of the mitochondria can be alleviated by irradiation with long-wave, deep red light: The radiation improves the function of certain membrane pumps in the mitochondria, which causes them to start producing more ATP again.
In 2020, researchers led by Glen Jeffery from University College London discovered that this light therapy also seems to work in humans: a daily “light shower” lasting several minutes with deep red light at a wavelength of 670 nanometers measurably improved the eyesight of their test subjects. “But we didn’t yet know how much light was needed for this and how long the effect would last,” explain the scientists.
Red light once for three minutes
So Jeffrey and his team have now carried out another pilot study. This time, the 20 test subjects looked into deep red LEDs for three minutes, whose output was only eight milliwatts per square centimeter (mW / cm 2 ) – significantly weaker than the 40 mW / cm 2 sup > the previous study. In addition, the participants between 37 and 70 years of age did not receive this light shower every day, but only once.
To check what role the time of day plays in this treatment, the scientists first carried out this experiment in the morning between eight and nine o’clock. In a second round they repeated it in the evening. All test persons were tested for their color-contrast vision before and after the treatment. This is taken over by the cones, one of the two types of visual cells in our retina.
Color contrast vision improved
The result: Despite the reduced amount of light and the only one-time irradiation, the red light was effective. The test subjects’ color contrast vision had improved by an average of 17 percent three hours after the “light shower”. In some older participants, the effect was around 20 percent, but in others it was significantly lower. A week later, the sensitivity for color contrasts in the test subjects was increased by around ten percent, as the team reports.
“The red light from a simple LED only once a week recharges the energy system of the aging retina cells,” says Jeffrey. “It’s almost like charging a battery.” However, this “charging” only works if it is done in the morning, as the second attempt showed: if the red light shower took place in the early evening, the effect was zero. “Mitochondria have changing work patterns, so they don’t react to light in the afternoon in the same way they do in the morning,” explains Jeffrey.
Chance of easy vision strengthening
According to the scientists, these results confirm that the aging mitochondria of the human retina react to deep red light – and that their energy production can be stimulated again as a result. In the current experiment, they only tested the effect on the mitochondria of the retinal cones. However, previous studies had already shown that the mitochondria of the rods react in a similar way, as the team explains.
This opens up a simple and affordable way to at least strengthen the eyesight that declines with age, at least a little, according to the team. “This simple intervention could significantly improve the quality of life of people in old age and alleviate the problems associated with deteriorating eyesight,” says Jeffrey. “In addition, the technology is simple and very safe: the energy of this long-wave light with 670 nanometers is not much higher than that already contained in natural daylight.”
He is confident that simple, inexpensive LEDs will soon be developed for these applications. “In the near future, you could have your weekly light shower while making coffee or commuting to work,” explains Jeffrey. (Scientific Reports, 2021; doi: 10.1038 / s41598-021-02311-1)
Those: University College London