Brief weekly exposure to red light can improve declining vision, study finds. The light “turns on” the mitochondria in the retina.
This discovery has wide implications, as mitochondria are the energy source of cells. A study by researchers at University College London, UK, showed that a brief application of the right kind of light can improve declining vision.
The study showed that a 3-minute exposure to intense red light in the morning, once a week, can improve vision that has declined due to aging, for up to a week. The researchers began their research on flies and mice, before working with the human study participants. The deep red light the researchers used had a specific hue, with a wavelength of 670 nanometers. The study is published in the journal Scientific Report.
The mitochondria of the retina
According to Professor Jeffery, the improvement in vision found in the study results from the fact that “the lights we use influence the mitochondria. These are highly conserved energy sources in cells. These are the cell batteries. Light increases the charge of the mitochondria and allows them to increase their energy yield which has diminished with age or disease. The chemical source of this energy is adenosine triphosphate (ATP). Vision decline after the age of 40 is linked to a 70% reduction in ATP, which means cells lack the energy to function properly.
The mitochondria of the eye in particular offer unique advantages for research. What is important about the retina is that it has more mitochondria than any other organ because it uses a lot of energy. In addition, the optical access of this treatment is easy. We can direct the light directly on the mitochondria of the retina, which is not possible for the mitochondria of the liver or the kidneys. Also the retina ages faster than any other organ, but one can simply test its function by asking people what they see, and thus define the perfect target for red light therapy.
The vision of color contrasts
The small study cohort, made up of both women and men, ranged in age from 34 to 70 years old. The researchers measured improvements in the participants’ vision by assessing their color contrast vision, or their ability to differentiate between colors. All participants had normal color contrast vision at the start of the trial. Some individuals were exposed to 3 minutes of intense red light in the morning, others in the afternoon. The red light was one stop stronger, about twice as strong as the general lighting in the test area.
The participants’ color contrast vision was tested three hours after exposure to red light and then a week later. The color contrast vision of participants exposed to red light in the morning improved by an average of 17%.
Timing is key
The researchers found that the application of light must take place in the morning to have an effect. They found no improvement in color contrast vision in participants exposed to afternoon light. One likely reason is that mitochondria follow the body’s circadian rhythm. Another possibility is related to the specific energy needs at the start of the day. The study also found that 3 minutes is the optimal length of light exposure and vision improvement lasts up to 1 week.
Three minutes is as effective as a 45 minute exposure.
The implications of the study go beyond improving vision. According to the researchers, “Mitochondria govern many aspects of our lives and we need a way to improve their health, especially as we age. The use of red light is now applied in a large number of laboratories and also in clinical trials. It will probably provide us with a very simple and inexpensive way to do this, with wide applicability.
Weeklong improved color contrasts sensitivity after single 670 nm exposures associated with enhanced mitochondrial function
* Presse Santé strives to transmit medical knowledge in a language accessible to all. In NO CASE can the information given replace medical advice.