From ScienceDaily@1337:3/111 to All on Wed Nov 24 21:30:34 2021
Morning exposure to deep red light improves declining eyesight
November 24, 2021
University College London
Just three minutes of exposure to deep red light once a week,
when delivered in the morning, can significantly improve declining
eyesight, finds a pioneering new study.
FULL STORY ==========================================================================
Just three minutes of exposure to deep red light once a week, when
delivered in the morning, can significantly improve declining eyesight,
finds a pioneering new study by UCL researchers.
========================================================================== Published in Scientific Reports, the study builds on the team's previous
work*, 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** 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' colour contrast vision when exposed to three minutes
of 670 nanometre (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 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.
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 nanometre (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 colour vision, and rods, which adapt
vision in low/dim light. This study focused on cones*** and observed
colour 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 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 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 colour vision was then tested again three
hours post exposure and 10 of the participants were also tested one week
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 colour vision tested again, it showed
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
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.
This research was funded by the Biotechnology and Biological Sciences
Research Council, and Sight Research UK.
To help meet the costs of this research and future research, Professor
Glen Jeffery's Lab at the UCL Institute of Ophthalmology receives
donations via UCL's Give Now platform.
*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.
========================================================================== Story Source: Materials provided by University_College_London. Note:
Content may be edited for style and length.
========================================================================== Journal Reference:
1. Harpreet Shinhmar, Chris Hogg, Magella Neveu, Glen Jeffery. Weeklong
improved colour contrasts sensitivity after single 670 nm exposures
associated with enhanced mitochondrial function. Scientific Reports,
2021; 11 (1) DOI: 10.1038/s41598-021-02311-1 ==========================================================================