Three minutes of morning exposure to deep red light can improve declining eyesight, new research has suggested.
Scientists wanted to look at what effect a single three-minute exposure would have while also using much lower energy levels than their previous studies.
Building on separate University College London (UCL) research in flies, the team also compared morning exposure to afternoon exposure.
According to the new study, on average there was a 17% improvement in participants’ colour contrast vision when exposed to three minutes of 670 nanometre (long wavelength) deep red light in the morning.
The researchers found this single exposure lasted for at least a week.
However, when the same test was conducted in the afternoon, no improvement was seen.
Scientists say their findings mark a breakthrough for eye health and should lead to affordable home-based eye therapies, helping the millions of people globally with naturally declining vision.
Lead author Professor Glen Jeffery, from the UCL Institute of Ophthalmology, said: “We demonstrate that one single exposure to long wave deep red light in the morning can significantly improve declining vision, which is a major health and wellbeing issue, affecting millions of people globally.
“This simple intervention applied at the population level would significantly impact on quality of life as people age and would likely result in reduced social costs that arise from problems associated with reduced vision.”
All participants were aged between 34 and 70, had no eye disease, completed a questionnaire regarding eye health prior to testing, and had normal colour vision (cone function).
This was assessed using a Chroma Test – identifying coloured letters that had very low contrast and appeared increasingly blurred, a process called colour contrast.
Using a provided LED torch-like device all 20 participants (13 female and 7 male) were exposed to three minutes of 670nm deep red light in the morning between 8am and 9am.
Three hours after exposure their colour vision was tested again, and 10 of the participants were also tested one week after exposure.
A few months on from the first test, six of the 20 participants conducted the same test in the afternoon, between 12pm to 1pm.
But when they had their colour vision tested again, it showed no improvement.
Prof Jeffery said: “Using a simple LED device once a week recharges the energy system that has declined in the retina cells, rather like re-charging a battery.
“And morning exposure is absolutely key to achieving improvements in declining vision: as we have previously seen in flies, mitochondria have shifting work patterns and do not respond in the same way to light in the afternoon – this study confirms this.”
The research, funded by the Biotechnology and Biological Sciences Research Council, and Sight Research UK, is published in Scientific Reports.