Looking at a deep red light for three minutes a day would limit the decline in sight.
- After 40 years, our visual system decreases considerably
- Study volunteers stared at a 670-nanometer deep red light beam for three minutes a day for two weeks
- Ability to detect colors and see in low light improved significantly in patients over 40
Fading vision is one of the markers of aging. In the UK there are currently around 12 million people over the age of 65 who are affected. In 50 years, this number will increase to about 20 million and all will experience some visual decline due to retinal aging. Researchers from the Institute of Ophthalmology at University College London (UCL) may have discovered a new home-based eye therapy that can delay and limit this decline. The results of this study were published in the Journal of Gerontology.
A deep red light of 670 nanometers
The visual system declines as one ages and this decline accelerates after age 40. “Your retinal sensitivity and color vision are both gradually undermined”, describes Professor Glen Jeffery, lead author of the study. This decline is characterized by the aging of cells in the retina of the eye and the rate of this aging is caused, in part, when the cell’s mitochondria, whose role is to produce energy (called ATP) and to stimulate cellular function, also begin to decline. Mitochondrial density is highest in retinal photoreceptor cells, which have high energy requirements. The retina ages faster than other organs, with a 70% reduction in ATP over life, causing a significant decline in the function of photoreceptors that lack the energy to perform their normal role.
The objective of the researchers is to fight effectively and simply against visual decline. “To try to stem or reverse this decline, we sought to reboot aging retinal cells with short bursts of long-wave light.”, recalls Glen Jeffrey. The researchers built on their previous findings in mice, bumblebees and flies, which all found significant improvements in retinal photoreceptor function when their eyes were exposed to deep red light of 670 nanometers (nm ), the unit of measurement for wavelength. “Mitochondria have specific light absorbance characteristics that influence their performance: longer wavelengths of 650-1000 nm are absorbed and improve mitochondrial performance to increase energy production”, noted the researcher. Retinal photoreceptors are made up of cones that mediate color vision and rods that provide peripheral vision and adapt vision in low light.
A marked improvement in the over 40s
For the study, 24 people, aged 28 to 72, without eye disease, were recruited. All of the participants’ eyes were tested for the sensitivity of their rods and cones at the start of the study. Rod sensitivity was measured in dark-adapted eyes by asking participants to detect weak light signals. The function of the cone was tested by identifying colored letters that have very low contrast and appear increasingly blurry. All participants were then given a small LED torch to take home to examine its 670nm deep red light beam for three minutes daily for two weeks. They were then retested for rod and cone sensitivity.
The researchers observed significant improvements in participants over 40 years old, but nothing changed in younger individuals. Cone color contrast sensitivity — the ability to detect colors — improved by up to 20% in some people aged 40 and older. The improvements were greatest in the blue part of the color spectrum, which is more vulnerable to aging. Rod sensitivity — the ability to see in low light — also improved significantly in this population, although it was less impressive than color contrast.
Technology at an affordable price
The results of this study are very promising and present a simple technique to combat the decline of our vision. “Our study shows that it is possible to dramatically improve vision that has declined in the elderly using simple brief exposures to light wavelengths that recharge the energy system that has declined in the cells of the retina, rather than charging a batterywelcomes Glen Jeffrey. The technology is simple and very safe, using deep red light of a specific wavelength, which is absorbed by retinal mitochondria which provide energy for cell function. Our devices cost around £12 [environ 13€, NDLR] to manufacture, so the technology is very accessible to members of the public.”
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