The eyes are already said to be the windows to the soul; now researchers are working to make them the windows to the body’s health as well. Jin Zhang, a professor of chemical and biochemical engineering at the University of Western Ontario, has developed contact lenses that could alert diabetics to their changing blood glucose levels. They change colors when the wearer’s glucose level shifts, allowing diabetics to monitor their health without the pain and inconvenience of drawing blood samples several times a day.

The lenses are made of special nanoparticles embedded in formed hydrogel. The nanoparticles are specially engineered to react chemically to glucose molecules in the wearer’s tears. When the glucose level experiences a significant change, the contact lenses change colors, alerting the wearer to the need to take action. Of course, for the lenses to be effective you would either have to have a mirror at hand at all times or be with someone who knows to check your eye color periodically. The Canada Foundation for Innovation liked Zhang’s idea so much that they awarded him more than $200,000 (Canadian) to continue his work on this and similar projects.