The chronic sleep problems that plague people as they get older may be due to normal aging processes that take place in the eye, new research, reported by the American Academy of Sleep Medicine, suggests.

In the study, published in the journal SLEEP, scientists from the Glostrup Hospital examined the eyes of 970 people to examine the relationship between eye health and sleep disruption. They concluded that one of the factors contributing to disturbed sleep among the elderly may be a yellowing of the lens that occurs naturally as a person ages and fatty deposits build up and thicken the eye gradually over time.

This yellowing inhibits blue light from reaching the retina, something that doesn't really affect a person's ability to see but might impact how much sleep-inducing melatonin is released in their brain.

According to the researchers, cataract surgery appears to enhance an older person's ability to process blue light. But, as yet, there is no way to remove age-induced eye-yellowing in the elderly.

Some scientists have hypothesized that melatonin supplements may provide a safe, natural way to help older people who have trouble sleeping.

In an analysis of several different studies involving the effects of melatonin on the sleeping patterns of elderly people, researchers from University Hospital Nijmegen in the Netherlands found that small amounts of melatonin were effective in enhancing sleep when given to certain, specially screened elderly people. In addition, none of the studies indicated negative side-effects associated with the melatonin supplement.

However, the researchers were also quick to point out that the more inclusive trials they examined had failed to indicate any significant benefit from the treatment. Thus, they concluded that there is not yet enough scientific evidence to suggest that melatonin would benefit older people who have trouble sleeping.