Significantly Improve Declining Eyesight in Just 3 Minutes a Week
By UNIVERSITY COLLEGE LONDON
Published in Scientific Reports, the study builds on the team’s
previous work,[1] which showed daily
three-minute exposure to longwave deep red light ‘switched on’ energy producing
mitochondria cells in the human retina, helping boost naturally declining
vision.
For this latest study, scientists
wanted to establish what effect a single three-minute
exposure would have, while also using much lower energy levels than their
previous studies. Furthermore, building on separate UCL research in flies[2] that found mitochondria display ‘shifting
workloads’ depending on the time of day, the team compared morning exposure to
afternoon exposure.
In summary, researchers found
there was, on average, a 17% improvement in participants’ color contrast vision
when exposed to three minutes of 670 nanometers (long wavelength) deep red
light in the morning and the effects of 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 the benefits of deep red light, highlighted by the 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 (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.”
Naturally declining vision and mitochondria
In humans around 40 years old,
cells in the eye’s retina begin to age, and the pace of this aging 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.
In studying the effects of deep
red light in humans, 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
nanometres (long wavelength) deep red light.
“Mitochondria have specific
sensitivities to long wavelength light influencing their performance: longer
wavelengths spanning 650 to 900nm improve mitochondrial performance to increase
energy production,” said Professor Jeffery.
Morning and afternoon studies
The retina’s photoreceptor
population is formed of cones, which mediate color vision, and rods, which
adapt vision in low/dim light. This study focused on cones[3] and observed color contrast sensitivity,
along the protan axis (measuring red-green contrast) and the tritan axis
(blue-yellow).
All the participants were aged
between 34 and 70, had no ocular disease, completed a questionnaire regarding
eye health prior to testing, and had normal color vision (cone function). This
was assessed using a ‘Chroma Test’: identifying colored letters that had very
low contrast and appeared increasingly blurred, a process called color
contrast.
Using a provided LED 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. Their color vision was then
tested again three hours post exposure and 10 of the participants were also tested
one week post exposure.
On average there was a
‘significant’ 17% improvement in colour vision, which lasted a week in tested
participants; in some older participants there was a 20% improvement, also
lasting a week.
A few months on from the first test
(ensuring any positive effects of the deep red light had been ‘washed out’) six
(three female, three male) of the 20 participants, carried out the same test in
the afternoon, between 12pm to 1pm. When participants then had their
color vision tested again, it showed zero improvement.
Professor 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.”
For this study the light energy
emitted by the LED torch was just 8mW/cm2, rather than 40mW/cm2, which
they had previously used. This has the effect of dimming the light but does not
affect the wavelength. While both energy levels are perfectly safe for the
human eye, reducing the energy further is an additional benefit.
Home-based affordable eye therapies
With a paucity of affordable deep
red-light eye-therapies available, Professor Jeffery has been working for no
commercial gain with Planet Lighting UK, a small company in Wales and others,
with the aim of producing 670nm infra-red eye ware at an affordable cost, in
contrast to some other LED devices designed to improve vision available in the
US for over $20,000.
“The technology is simple and very
safe; the energy delivered by 670nm long wave light is not that much greater
than that found in natural environmental light,” Professor Jeffery said.
“Given its simplicity, I am
confident an easy-to-use device can be made available at an affordable cost to
the general public.
“In the near future, a once a week
three-minute exposure to deep red light could be done while making a coffee, or
on the commute listening to a podcast, and such a simple addition could
transform eye care and vision around the world.”
Study limitations
Despite the clarity of the
results, researchers say some of the data are “noisy”. While positive effects
are clear for individuals following 670nm exposure, the magnitude of
improvements can vary markedly between those of similar ages. Therefore, some
caution is needed in interpretating the data. It is possible that there are
other variables between individuals that influence the degree of improvement
that the researchers have not identified so far and would require a larger
sample size.
Notes
Declining eyesight improved by looking at deep red light & Journals of Gerontology
‘A day in the life of mitochondria reveals shifting workloads’ in
Scientific Reports
Only cones not rods were tested in
this study; similar previous research identified a comparable effect on cones
and rods, satisfying the team any effect on cones could be translated to rods.
Reference: “Weeklong improved
colour contrasts sensitivity after single 670nm exposures associated with
enhanced mitochondrial function” 24 November 2021, Scientific Reports.
DOI: 10.1038/s41598-021-02311-1
This research was funded by the
Biotechnology and Biological Sciences Research Council, and Sight Research UK.
