Human tears could carry a flood of useful information. With just a few drops, a new technique can spot eye disease and even glimpse signs of diabetes.

Researchers Say, It’s possible the human tears could open a window for scientists to peer into the entire body.

Like saliva and urine, tears contain tiny sacs stuffed with cellular messages (SN: 9/3/13). If scientists could intercept these microscopic mailbags, they see what’s happening inside the body. 

But collecting enough of these sacs, called exosomes, is tricky. Unlike fluid from other body parts, just a trickle of liquid leaks from the eyes.

So research team devised a new way to capture the sacs from tiny volumes of tears.

First, the team collected tears from participants. Then, the added a solution containing the tears to a device with two nanoporous membranes, vibrated the membranes and sucked the solution through.

Within minutes, the technique lets small molecules escape, leaving the sacs behind for analysis.

The results gave scientists an eyeful. Different types of dry-eye disease shed their own molecular fingerprints in people’s tears, the team found. 

What’s more, tears could potentially help doctors monitor how a patient’s diabetes is progressing. 

Now, the scientists want to tap tears for evidence of other diseases as well as depression or emotional stress, says study coauthor Luke Lee, a bioengineer at Harvard Medical School. 

“This is just the beginning,” Luke Lee says. “Tears express something that we haven’t really explored.”