A single three-minute exposure to deep red light in the morning can significantly improve aging adults' color vision for up to a week, according to research from University College London published in Nature.
The study found that shining 670 nanometer deep red light into participants' eyes for three minutes between 8-9am enhanced their ability to detect colors by up to 20% in some older adults. The improvements lasted at least seven days after a single brief exposure.
"We found these improvements were only possible when the light exposure occurred in the morning. When we tried it in the afternoon, there was no effect," explains lead researcher Glen Jeffery. This timing appears linked to the natural daily rhythms of cells' mitochondria — the microscopic powerhouses that generate energy.
The researchers tested color vision in 20 people aged 34-70 years, focusing on their ability to detect subtle differences along blue-yellow and red-green color scales. The largest improvements occurred in distinguishing blue-yellow contrasts, with an average 17% enhancement across all participants.
The treatment uses very low energy levels — about 8 milliwatts per square centimeter, which is less than 10 times brighter than natural environmental light. This makes it both safe and practical as a potential therapy.
"This simple and highly economic intervention applied at the population level will significantly impact the quality of life in the elderly," says Jeffery. "Humans live in a world where we now rarely employ rod function exclusively because we control our light environment. This in combination with the fact that unlike rods, ageing cones do not die but have reduced function highlights the critical need to improve cone ability in progressively ageing populations."
Previously:
• Staring at a $16 red flashlight improved eyesight in people over 40
