While health experts have wondered what might trigger age-related conditions such as insomnia, memory loss, and even depression, few suspected that the eyes would be to blame. New research indicates that the gradual yellowing of the eye lens and narrowing of the pupil , which occur with age, disturb the body’s “circadian rhythm,” or body clock. As less sunlight penetrates the eye lens, fewer of the retinal cells that regulate the body’s circadian rhythm are activated. In turn, a range of health problems may arise. Circadian rhythms rely on light to set cyclical hormonal and physiological processes in motion that get the body moving in the morning and slow it down at night for rest and repair.
P.S. It is estimated that by age 45, the photoreceptors in the eyes of the average adult receive only 50 percent of the (blue) light need to fully stimulate the circadian rhythm. By age 55, the percentage dips to 37%.