For years scientists have tried to uncover why memory loss increases with age. While previous research has attributed it to heart disease, high cholesterol, obesity and inactivity, researchers at the University of Kansas School of Medicine, have gathered a provocative body of evidence that suggests that the aging of the eye could be the culprit.

As individuals grow older the lens of their eye slowly yellows and the pupil begins to narrow, causing a disruption of the body’s clock or internal rhythm.

As the amount of sunlight able to reach the major cells located within the retina grows scarce a number of bodily functions are thrown off. This is what researchers now believe is at the root of a host of health problems that begin as one grows older.

Drs. Martin Mainster and PatriciaTurner estimate that by age 45, the photoreceptors, the section of the retina that converts light into signals that control the body, of the average adult receive merely 50 percent of the light needed to function properly. At age 55, this number drops to 37 percent, and by the time one is 75 years old, the eyes receive only 17 percent of the precious fuel it needs.

Several additional studies support this theory. For example one published in the journal Experimental Gerontology as well as another published in The Journal of Biological Rhythms concluded that exposure to the same amount of bright light that makes a young person feel alert, have better memory retention and experience improved mood has no effect on older people.

Another study conducted in Sweden took this concept one step further studying patients who underwent cataract surgery, replacing the clouded portion of their lens with a clear prosthetic, allowing for more light to find its way through. The participants experienced reduced daytime drowsiness, improved reaction time, and significant reduction of insomnia.

Mainster and Turner are optimistic that further research will reveal cataract surgery also improves individual’s propensity for other health conditions including cancer and heart disease. Until then the doctors suggest that older individuals make more of a concerted effort to expose themselves to bright sun or artificial light on a regular basis to help keep their eyes and body healthier.