A new study, which researchers say is the first of its kind, says the retina may also be able to provide us with an easy, noninvasive way to determine our body's true biological age -- which may or may not mirror our chronological age.

"The retina offers a unique, accessible 'window' to evaluate underlying pathological processes of systemic vascular and neurological diseases that are associated with increased risks of mortality," wrote study author Dr.

Using a deep learning model, which is a form of machine learning, the researchers estimated a "retinal age gap" between the actual biological health of the eye and the person's age since birth.

There was a 2% increase in the risk of death from any cause for each year of difference between a person's actual age and the older biological age identified in the eye, the study found.

That might be due to a smaller number of such cases in the population studied, the researchers said, or to improvements in cancer and heart disease treatments.

"Our novel findings have determined that the retinal age gap is an independent predictor of increased mortality risk, especially of non-cardiovascular disease and non-cancer mortality," wrote He and his team.