Staring at a deep red light for three minutes a day can significantly improve declining eyesight, finds a new study, which may bring immense potential to bring about new affordable home-based eye care technique or therapy, helping millions of people globally with naturally declining vision as they age.
The first of its kind in humans study by scientists at the UCL Institute of Ophthalmology was published in the Journals of Gerontology. Once over 40, the retinal sensitivity and colour vision gradually decline and with an ageing population, this is an increasingly important issue. The new method can reverse this decline, by rebooting the retina’s ageing cells with short bursts of longwave light.
In humans around 40 years-old, cells in the eye’s retina begin to age caused, in part, when the cell’s mitochondria, whose role is to produce energy (known as ATP) and boost cell function, also start to decline. In the UK there are currently around 12 million people aged over 65 and in 50 years this is estimated to increase to around 20 million.
Retina Decline Reversible
Mitochondrial density is greatest in the retina’s photoreceptor cells, which require high energy and thus, the retina ages faster than other organs, with a 70% ATP reduction over life, causing a significant decline in photoreceptor function. Researchers built on their previous findings in mice, bumblebees and fruit flies, when their eyes were exposed to 670 nanometre (long wavelength) deep red light.
“Mitochondria have specific light absorbance characteristics influencing their performance: longer wavelengths spanning 650 to 1000nm are absorbed and improve mitochondrial performance to increase energy production,” said Professor Glen Jeffery, lead author and scientist at UCL Insitutute of Ophthalmology. The retina’s photoreceptor population is formed of cones, which mediate colour vision and rods, which provide peripheral vision and adapt vision in low or dim light.
For the study, 24 people (12 male, 12 female), aged between 28 and 72, who had no ocular disease, were recruited. All 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 (with pupils dilated) by asking participants to detect dim light signals in the dark, and cone function was tested by subjects identifying coloured letters that had very low contrast and appeared increasingly blurred, a process called colour contrast.
All participants were then given a small LED torch to take home and were asked to look into* its deep red 670nm light beam for three minutes a day for two weeks. They were then re-tested for their rod and cone sensitivity
Researchers found the 670nm light had no impact in younger individuals, but in those around 40 years and over, cone colour contrast sensitivity (the ability to detect colours) improved by up to 20% in some people aged around 40 and over. Improvements were more significant in the blue part of the colour spectrum that is more vulnerable in ageing. Rod sensitivity also improved significantly in them though less than colour contrast.
Professor Jeffery said: “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 re-charging a battery. The technology is simple and very safe, using a deep red light of a specific wavelength, that is absorbed by mitochondria in the retina that supply energy for cellular function.
The team is planning to make devices costing about £12 to make, so the technology is highly accessible to the public.