Declining eyesight in humans was shown to improve when subjects looked at a deep red 670-nm light beam for three minutes a day for two weeks, according to a study led by researchers at University College London. The approach, which improves mitochondrial function in the retina, could lead to affordable home-based eye therapies, helping the millions of people globally with naturally declining vision. Twenty-four women and men ages 28 to 72, who had no ocular disease, were tested for the sensitivity of their eyes’ rods and cones at the start of the study. All participants were then given a small LED torch to take home and were asked to look into its deep red light for three minutes a day for two weeks. They were then retested for their rod and cone sensitivity The 670-nm light had no impact in younger individuals, but significantly improved rod and cone sensitivity in those around 40 years and older. Cone color contrast sensitivity (the ability to detect colors) improved by up to 20% in some people around 40 years and older. Improvements were more significant in the blue part of the color spectrum, which is affected more by aging. Rod sensitivity (the ability to see in low light) also improved in those 40 and over, although less than color contrast. This is an example of the hand-held LED torch used in study. Courtesy of University College London. Cells in the retina begin to age in humans at around 40 years old. The pace of this aging is caused, in part, when the cell’s mitochondria, whose role is to produce energy and boost cell function, also start to decline. Mitochondrial density is greatest in the retina’s photoreceptor cells, which have high energy demands. As a result, the retina ages faster than other organs. “Your retinal sensitivity and your color vision are both gradually undermined, and with an aging population, this is an increasingly important issue,” professor Glen Jeffery said. “To try to stem or reverse this decline, we sought to reboot the retina’s aging cells with short bursts of longwave light. “Mitochondria have specific light absorbance characteristics influencing their performance: Longer wavelengths spanning 650 to 1000 nm are absorbed and improve mitochondrial performance to increase energy production,” Jeffery said. The researchers built on their previous findings in mice, bumblebees, and fruit flies, which all found significant improvements in the function of the retina’s photoreceptors when their eyes were exposed to 670-nm (long wavelength) deep red light. “Our study shows that it is possible to significantly improve vision that has declined in aged individuals using simple brief exposures to light wavelengths that recharge the energy system that has declined in the retina cells, rather like recharging a battery,” Jeffery said. Using the technology is safe and simple, according to Jeffery. The device costs only about £12 ($15) to make, so it could be made accessible to a large portion of the population. The research was published in the Journal of Gerontology: Series A (www.doi.org/10.1093/gerona/glaa155).