Crappy Old Age Eyesight Causes Crappy Old Age Sleep
At least, it’s an interesting theory.
I bet they can eventually just figure out the right chemicals to take instead of whatever is triggered by your eyes. But maybe some signals go electrically (like all vision) into the brain, in a way that no pill could reproduce.
Vitamin D (2000-6000 IU) taken right when you wake up is supposed to do a lot to normalize the body’s day/night cycle.
The gradual yellowing of the lens and the narrowing of the pupil that occur with age disturb the body’s circadian rhythm, contributing to a range of health problems, these studies suggest. As the eyes age, less and less sunlight gets through the lens to reach key cells in the retina that regulate the body’s circadian rhythm, its internal clock.“We believe the effect is huge and that it’s just beginning to be recognized as a problem,” said Dr. Patricia Turner, an ophthalmologist in Leawood, Kan., who with her husband, Dr. Martin Mainster, a professor of ophthalmology at the University of Kansas Medical School, has written extensively about the effects of the aging eye on health.Circadian rhythms are the cyclical hormonal and physiological processes that rally the body in the morning to tackle the day’s demands and slow it down at night, allowing the body to rest and repair. This internal clock relies on light to function properly, and studies have found that people whose circadian rhythms are out of sync, like shift workers, are at greater risk for a number of ailments, including insomnia, heart disease and cancer.“Evolution has built this beautiful timekeeping mechanism, but the clock is not absolutely perfect and needs to be nudged every day,” said Dr. David Berson, whose lab at Brown University studies how the eye communicates with the brain.So-called photoreceptive cells in the retina absorb sunlight and transmit messages to a part of the brain called the suprachiasmatic nucleus (S.C.N.), which governs the internal clock. The S.C.N. adjusts the body to the environment by initiating the release of the hormone melatonin in the evening and cortisol in the morning.Melatonin is thought to have many health-promoting functions, and studies have shown that people with low melatonin secretion, a marker for a dysfunctional S.C.N., have a higher incidence of many illnesses, including cancer, diabetes and heart disease.It was not until 2002 that the eye’s role in synchronizing the circadian rhythm became clear. It was always believed that the well-known rods and cones, which provide conscious vision, were the eye’s only photoreceptors. But Dr. Berson’s team discovered that cells in the inner retina, called retinal ganglion cells, also had photoreceptors and that these cells communicated more directly with the brain.These vital cells, it turns out, are especially responsive to the blue part of the light spectrum.