Gazing bright red for three minutes a day can significantly improve declining vision, finds a new study conducted by UCL, the first of its kind in humans.
Scientists believe that the discovery, published in the Gerontology journals, could signal the dawn of new affordable home-based eye therapies, helping millions of people around the world with a naturally declining vision.
In the UK there are currently around 12 million people over the age of 65: in 50 years this will increase to around 20 million and all will have some visual decline due to aging of the retina.
Lead author, Professor Glen Jeffery (UCL Institute of Ophthalmology) said: “As we age, your visual system decreases significantly, particularly once we are over 40.
“Your retinal sensitivity and your vision of colors are both gradually weakened and, with the aging of the population, this is an increasingly important problem.
“To try to stem or reverse this decline, we tried to restart the aging cells of the retina with short bursts of long wave light.”
In humans around 40 years of age, the cells in the retina of the eye begin to age and the rhythm of this aging is caused, in part, when the mitochondria of the cells, whose role is to produce energy (known as ATP) and increase the cellular function, also begin to decline.
Mitochondrial density is highest in the photoreceptor cells of the retina, which have high energy needs. As a result, the retina ages faster than other organs, with a 70% reduction in ATP over the course of life, causing a significant decline in the function of photoreceptors as they lack the energy to play their normal role.
The researchers built their previous findings on mice, bumble bees and fruit flies, which all found significant improvements in retinal photoreceptor function when their eyes were exposed to a deep red light of 670 nanometers (long wavelength ).
“Mitochondria have specific light absorption characteristics that influence their performance: longer wavelengths ranging from 650 to 1000nm are absorbed and improve mitochondrial performance to increase energy production,” said Professor Jeffery.
The population of photoreceptors in the retina is made up of cones, which mediate color vision and rods, which provide peripheral vision and adapt vision in low / low light conditions.
For the study, 24 people (12 males, 12 females), aged between 28 and 72 years, who had no eye conditions were hired. All participants’ eyes were tested for the sensitivity of their rods and cones at the start of the study. The sensitivity of the rod was measured in adapted dark eyes (with dilated pupils) by asking participants to detect dim light signals in the dark, and the function of the cone was tested by subjects who identified colored letters that had a very high contrast low and appeared increasingly blurred, a process called color contrast.
All participants were then given a small LED flashlight to take home and asked to examine its 670 nm intense red light beam for three minutes a day for two weeks. They were then tested again for the sensitivity of the barrel and the cone
The researchers found that light at 670 nm had no impact on younger individuals, but significant improvements were achieved in those around 40 years of age.
The sensitivity to the contrast of the color of the cone (the ability to detect colors) has improved by up to 20% in some people aged 40 and over. The improvements were most significant in the blue part of the color spectrum which is most vulnerable to aging.
The sensitivity of the auction (the ability to see in low light conditions) also improved significantly in people over the age of 40, although lower than the color contrast.
Professor Jeffery said: “Our study shows that it is possible to significantly improve the decreased vision in older individuals by using simple short exposures at light wavelengths that recharge the energy system that has decreased in retinal cells, rather how to recharge a battery.
“The technology is simple and very safe, using a deep red light of a specific wavelength, which is absorbed by the mitochondria in the retina which provide energy for cellular function.
“Our devices cost around £ 12 to make, so the technology is highly accessible to members of the public.”