Red light rejuvenates aging eyes

Scientists believe the discovery, published in the Journals of Gerontology, could signal the dawn of new affordable home-based eye therapies, helping the millions of people globally with naturally declining vision.

In the UK there are currently around 12 million people aged over 65: in 50 years this will increase to around 20 million and all will have some degree of visual decline because of retinal ageing.  

Lead author, Professor Glen Jeffery (UCL Institute of Ophthalmology) said: “As you age your visual system declines significantly, particularly once over 40.    

“Your retinal sensitivity and your colour vision are both gradually undermined, and with an ageing population, this is an increasingly important issue.

“To try to stem or reverse this decline, we sought to reboot 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, and the pace of this ageing is 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.

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, with a 70% ATP reduction over life, causing a significant decline in photoreceptor function as they lack the energy to perform their normal role.

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 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 Jeffery.

The retina’s photoreceptor population is formed of cones, which mediate colour vision and rods, which provide peripheral vision and adapt vision in low/dim light.

Reference: https://www.liebertpub.com/doi/10.1089/photob.2021.0005