Aging Eyes Linked to Heart Disease, Diabetes and Cancer

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Memory loss, we think it’s just another part of getting old, but science is beginning to disagree. In a fascinating new research study, a team of scientists are setting out to explore the idea that the gradual yellowing and narrowing of the pupil some experience with age may have a direct link to memory loss, diseases of the heart, insomnia, diabetes, cancer and even depression.

The body’s circadian rhythm (internal clock) feeds on nutrients that the sun provides us. As the eyes age, less and less sunlight gets through the lens to reach key cells in the retina that regulate the body’s internal clock. Martin Mainster, a professor of ophthalmology at the University of Kansas Medical School, explains that circadian rhythms use light to trigger hormonal and physiological processes signaling the body that it’s time to wake or when to begin winding down for sleep to heal.

Photoreceptive cells in the retina absorb sunlight and transmit messages to a part of the brain called the suprachiasmatic nucleus (SCN). The SCN adjusts the body to the environment by initiating the release of hormones cortisol in the morning and melatonin in the evening. Previous studies have shown that people with low melatonin levels and with their circadian rhythms out of sync have a higher risk of insomnia, cancer, diabetes and heart disease.

In 2002, Dr. David Berson and a team from Brown University in Providence, Rhode Island, made a breakthrough discovery in better understanding how the circadian rhythm worked. Previously, it was thought that well known rods and cones, which provide conscious vision, were the eye’s only photoreceptors for the eye. But in 2002, Dr. Brown’s team discovered that certain cells in the internal retina, called retinal ganglion cells, also had photoreceptors that communicated more directly with the brain. These retinal ganglion cells appeared to be most responsive to ‘blue light’, and used it to dictate the body’s internal clock.

Blue light, of course, is widely used in electronics and energy-efficient light bulbs, which frequent exposure to, could have a negative effect on our body’s natural synchronization. When a research team in Sweden tested Berson’s theory by implanting intraocular lenses in the eyes of cataract patients, they found that the incidence of insomnia and daytime sleepiness was significantly reduced. The blue light helped them sleep and function better. Currently, about one-third of these intraocular lenses implanted worldwide are ‘blue-light-blockers’ intended to reduced the risk of macular degeneration by limiting exposure to potentially damaging light rays from the sun. But there is no evidence to suggest that these blue-light-blockers are preventing damage or slowing degeneration at all.

So what can you do to reduce the risks of cancer, diabetes and heart disease? Experts are saying it’s as easy as making an effort to expose yourself to bright sunlight, or bright indoor lighting. Allow your eyes to absorb more natural blue light during the times you are meant to be awake, and less blue light (electronics, etc.) when you are winding down to sleep. By learning to stabilize and regulate your natural circadian rhythm, you are giving your body enough power it needs to function while awake, and regenerate while you sleep.

Barbara Jaworski is Canada’s leading expert on boomers, chief KAA-Boomer of the Workplace Institute and author of Rebel Retirement – A KAA-Boomer’s Guide to Creating and Living an Explosive Second Act. You can find out more at

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