Mitochondria play critical roles in cellular energy and function. The decline in mitochondrial quality and activity that occurs with aging is linked to the development of a wide range of age-related diseases. The highest concentrations of mitochondria in the body are found in the rods and cones of the eyes, where they support multiple aspects of vision. Findings from a new study indicate that viewing a red light restores mitochondrial function in the eyes of older adults.

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 1,000-nanometer range, improve mitochondrial function and enhance ATP production. Red light has the longest wavelengths on the visible spectrum.

The intervention study involved 24 adults between the ages of 28 and 72 years who had no eye disease. The participants were instructed to look at a red light with their dominant eye every morning for three minutes every day for two weeks. The authors of the study assessed the participants' rod and cone sensitivity before and after the intervention.

The authors of the study noted that the participants' rod and cone performance declined considerably after the age of 40. However, exposure to red light (670 nanometers) improved both rod and cone function in the participants over the age of 40. The participants' ability to detect colors – a function of cone sensitivity – improved by up to 20 percent in some participants. These findings suggest that simple light therapies show promise as a means to ameliorate visual loss in older adults. Larger studies are needed to confirm these findings.

• Link to study abstract.