Decreased vision is one of the markers of aging. According to the Centers for Disease Control (CDC) in the US, there are currently about 12 million people over the age of 40 affected. And as they get older all of them will suffer some loss of vision due to the aging of the retina. Researchers at the University College London Institute of Ophthalmology (UCL) may have discovered a new eye therapy that can be used at home to slow and limit this decline. The results of this study have been published in the Journal of Gerontology.
A deep red light of 670 nanometers
Eyesight decreases with age, and this decrease accelerates after the age of 40. “Both your retinal sensitivity and color vision are gradually undermined,” says Professor Glen Jeffery, lead author of the study. This decline is characterized by the aging of the retinal cells of the eye, and the speed of this aging is partly caused by the fact that the mitochondria of the cell whose job it is to produce energy (called ATP) and stimulate cell function are also beginning to decline. The mitochondrial density is higher in the photoreceptor cells of the retina, which have a high energy requirement.
The retina ages faster than other organs, with ATP levels being reduced by 70% over the course of a lifetime. This gradual decrease in ATP levels results in a significant decrease in the function of photoreceptor cells because they no longer have the energy necessary to perform their normal tasks.
The aim of the researchers in this study is to combat visual impairment effectively and easily. “To stop or reverse this decline, we have tried to restart the aged cells of the retina with short, long-wave light flashes,” says Jeffrey. The researchers based their earlier findings on bumblebees, rats and fruit flies, all of which found significant improvements in the function of their retinal photoreceptors when their eyes were exposed to deep red light of 670 nanometers (nm), the unit of measurement for wavelength.
“Mitochondria have specific light absorption properties that affect their performance: Longer wavelengths of 650 to 1,000 nm are absorbed and improve the performance of mitochondria to increase energy production,” the researcher discovered. Retinal photoreceptors consist of cones that measure chromatic vision and rods that enable peripheral vision and adjust vision in low light.
Significant improvement in the age group over 40
For the study, 24 persons aged between 28 and 72 years without eye diseases were recruited. The eyes of all participants were tested at the beginning of the study for the sensitivity of their rods and cones. The sensitivity of the rods was measured in eyes adapted to darkness, with participants asked to detect faint signs of light. The function of the cone was tested by identifying colored letters that have very little contrast and appear increasingly blurred. All participants were then given a small LED flashlight to take home and then look into their 670 nm deep red light beam for three minutes every day for two weeks. After the 2 weeks has ended they were then subjected to a new rod and cone sensitivity test.
Researchers found significant improvements in participants over 40 years of age, but no changes were seen in younger people. The color contrast sensitivity of the cones – the ability to recognize colors – improved by up to 20% in some people aged 40 and over. The improvements were greatest in the blue part of the color spectrum, which is more susceptible to aging. The sensitivity of the rods – the ability to see in low light – also improved significantly in this population, although this was less impressive than for color contrast.
Technology at an affordable price
The results of this study are very promising and represent a simple and affordable technique that can be used to combat the decline in our vision. “Our study shows that it is possible to significantly improve vision that has deteriorated in older people by using short exposures to wavelengths of light that recharge the energy system that is depleted in the cells of the retina just like when recharging a battery,” says Glen Jeffrey. The technology is simple and very safe. It uses deep red light of a specific wavelength that is absorbed by the retinal mitochondria, which provide energy for cell function. Most importantly the LED flashlights used in this experiment are not expensive to make and thus would be easily available to the general public. The estimated cost of manufacturing these LED lights is around $15 per unit.