Staring at a red light bulb for three minutes every night may reduce age-related vision loss. A team of researchers led by neuroscientist Glenn Jeffrey, a professor in the Department of ophthalmology at University College London, has now provided strong evidence for the idea.
According to a report on the Website of Deutsche Welle radio on July 11, 24 volunteers between the ages of 28 and 72 took part in the experiment, all of whom had no eye problems. The researchers first tested the sensitivity of light-sensitive cells in the volunteers’ retinas. These photoreceptor cells consist of cones and rods. Cones are responsible for color perception, while rods are important for peripheral vision and for vision at dusk and in the dark.
To measure the performance of the cones, the subjects had to identify letters of color that were barely visible and were getting blurry, the report said. The scientists then gave the subjects small LED flashlights and had them stare at the flashlight’s crimson light for three minutes a day for two weeks, then repeatedly tested the sensitivity of their rods and cones.
Experiments show that red light treatment is only effective in the elderly. In people over 40, red light increased the performance of their cones by a fifth. There was no change in the younger subjects.
In particular, the improvement in the ability to recognize blue is significant, which is usually the color range with the fastest loss of vision. At the same time, the rod cell performance also improved significantly. But researchers caution that people should use red lights appropriately. The retina is a highly sensitive organ, and do not use lamps that have not been medically tested, certified or made at home.
As people enter middle and old age, photoreceptor cells in the retina change, leading to decreased vision. One reason is retinal cell senescence. This is mainly due to the deterioration of mitochondrial performance in the cell. Mitochondria are thought to be the power generators of cells, providing energy in the form of the energy carrier adenosine triphosphate (ATP).
If the mitochondria’s performance deteriorates, the cell will not be able to maintain its function. Photoreceptors in the retina have the highest concentration of mitochondria, and these cells require a lot of energy.
This is why vision is affected earlier and more severely than other organs in the aging process, the report said. Over the course of a person’s life, the production of adenosine triphosphate in retinal cells ends up being reduced by an average of 70 per cent, thus significantly reducing photoreceptor performance.
“Mitochondria absorb light at wavelengths between 650 and 1,000 nanometers, so their performance is enhanced and their productivity increased,” Jeffrey explained. The researchers knew from previous studies that when bumblebees, fruit flies and mice were exposed to a wavelength of 670 nanometers, or deep red light, the function of photoreceptor cells in the retina was significantly improved.
The flashlight in use today also has a wavelength of 670 nanometers. Jeffrey likens light therapy to charging a battery. “Exposing older people to light at wavelengths suitable for charging the retinal cell energy system for a short period of time can significantly improve vision in older people,” he said.