Aging, the collective physiological, functional, and mental changes that accrue in a biological organism over time, affects different organs and organ systems at different rates. The effects of aging on the eyes begins around the age of 40 years, when retinal cells called rods and cones undergo rapid decline due to mitochondrial dysfunction and loss, markedly impairing eyesight. Findings from a recent study suggest that a single exposure to red light in the morning improves eyesight.
Mitochondria have specific light absorbance characteristics that modulate their performance. For example, the mitochondrial electron transport chain is photosensitive to certain wavelengths of light. As a result, exposure to longer wavelengths, such as those in the 650 to 1000 nanometer range, improve mitochondrial function and enhance ATP production. Red light has the longest wavelengths on the visible spectrum, and previous research indicates that exposure to red light restores mitochondrial function in the eyes of older adults.
The current study involved 20 adults between the ages of 34 and 70 years who had no eye disease. The participants looked at a red light (670 nanometers) with their dominant eye in the morning (between 8 a.m. and 9 a.m.) or afternoon (between noon and 1 p.m.) for three minutes. The authors of the study assessed the participants' rod and cone sensitivity before the single-session intervention and again at three hours and one week post-intervention.
They found that after the age of 40 years the participants' rod and cone performance underwent marked decline. These declines were rescued by exposure to red light, but only when the exposure occurred in the morning. Color sensitivity, a feature of the cone cells, improved by up to 20 percent in older participants.
These findings suggest that simple light therapies show promise as strategies to ameliorate vision loss in older adults. Interestingly, sulforaphane, a bioactive compound derived from some cruciferous vegetables, helps protect retinal cells against oxidative stress – a driver of mitochondrial dysfunction. Learn more about sulforaphane in this episode featuring Dr. Jed Fahey.
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