Once Weekly AM Exposure to Long Wavelength Light for 3 Minutes Could Improve Declining Color Vision

Article: Morning exposure to deep red light improves declining eyesight
Source: University College London (U.K.)
Published: November 24, 2021
Article: Declining Eyesight Could Be Given a Boost by Short Morning Doses of Seeing Red
Source: ScienceAlert
Published: November 27, 2021

Improvement in color contrast sensitivity at 1 week
post-exposure for the tritan (blue-yellow) axis (top)
and the protan (red-green) axis (bottom)

Mitochondria are the energy organelles of eukaryotic cells, including the eye's photoreceptors, where they exist in high concentration to support the transduction of light that leads to vision. The function of mitochondria naturally decline with age, with an estimated 70% ATP reduction over a lifetime. Some researchers in the U.K. are looking into ways to boost their activity through deep wavelength light stimulation. Specifically, these researchers are translating results they had earlier compiled in animal models such as mice, bumblebees and fruit flies, all showing that exposure to 670 nm (long wavelength) deep red light produced significant improvements in the function of the retina’s photoreceptors. An earlier study from 2020 saw positive results in color vision after 3 minutes of daily exposure to 670 nm light in human subjects. In the present study, the researchers wanted to hone in on the effect of a single 3-minute exposure of deep red light and also reduce the LED wattage from 40mW/cm2 to 8mW/cm2, noting that both are safe. They recruited 20 participants between 34 and 70 years of age and asked them to use a provided LED device emitting 670 nm deep red light for 3 minutes in the morning between 8am and 9am. The participants' color vision was tested 3 hours later, and 10 of the participants were tested again one week later. On average, at 3 hours post-exposure, the participants saw improvement in color contrast sensitivity threshold of 17% for the tritan (blue-yellow) axis and 12% for the protan (red-green) axis. At one week post-exposure, the improvements were maintained at 10% for the tritan axis and 8% for the protan axis. Separate research in flies revealed that mitochondria have "shifting workloads" depending on the time of day. The researchers confirmed this finding in humans when they tested 6 of the 20 participants again several months later for an afternoon protocol from 12pm to 1pm; the subsequent color vision tests showed no improvement in that case. The authors acknowledge a lot of "noise" and variability in their data; nonetheless, these early results are encouraging for improvement of mitochondria-related decline in color contrast sensitivity in older age.

My rating of this study: ⭐

Shinhmar H, Hogg C, Neveu M, et al. "Weeklong improved colour contrasts sensitivity after single 670 nm exposures associated with enhanced mitochondrial function." Scientific Reports.  11:22872. 24 November 2021. https://doi.org/10.1038/s41598-021-02311-1