As we age, mitochondrial functionality declines, reducing the production of ATP, the main source of cellular energy. Photoreceptors in the retina, which have high energy demands, are particularly affected by this process. Red light in the range of 650–900 nm has previously been proven effective in restoring mitochondrial function and slowing retinal degeneration. Moreover, this 2021 study revealed another surprising finding: even short exposure to red light with a wavelength of 670 nm can significantly improve color contrast sensitivity.
Short-term exposure to red light (670 nm) improves color contrast sensitivity for up to a week
The clinical study was conducted on individuals aged 37 to 70 and showed that short, morning, three-minute exposure to 670 nm light with an intensity of 8 mW/cm² at the cornea significantly improved color contrast mediated by cones to levels typical in younger populations. Red light therapy could thus serve as a preventive measure against the loss of full-color vision in old age. The study also demonstrated that red light might play a key role in supporting eye health. Therefore, when selecting light sources for daytime lighting, it is important to focus on balanced spectra with sufficient red components.
The effect of red light persisted for a week after exposure
Improved color contrast sensitivity in older adults persisted for up to a week. The improvement in color contrast sensitivity was 17% for the tritan axis (blue-yellow visual axis) after the first exposure, and for the protan axis (red-green visual axis), there was an average improvement of 12%. These improvements were observed three hours after exposure and remained evident a week later. The mechanism of this effect likely relates to the improved function of mitochondria due to light exposure, which, though not permanent, provides a temporary boost to the energy production capacity of retinal cells.
Optimal effects were achieved with exposure in the morning hours (8–9 AM)
According to the study, this timing is likely linked to the daily cycle of mitochondrial activity, as mitochondria exhibit functional changes throughout the day. Morning exposure can optimize ATP production and increase cell efficiency, allowing retinal cells to respond better to light. Aligning light therapy with the body’s natural rhythms could significantly enhance the effectiveness of such interventions in improving vision, especially in older adults.
Translated using AI
