Tears may help diagnose Parkinson's early: Study

Researchers found differences in the levels of a protein, alpha-synuclein, in the tears of people with Parkinson's compared to others

Testing tears may be a reliable, inexpensive and noninvasive way to diagnose Parkinson’s disease early, a study has found.

Researchers investigated tears because they contain various proteins produced by the secretory cells of the tear gland, which is stimulated by nerves to secrete these proteins into tears.

“We believe our research is the first to show that tears may be a reliable, inexpensive and noninvasive biological marker of Parkinson’s disease,” said Mark Lew from the University of Southern California in Los Angeles.

Since Parkinson’s can affect nerve function outside of the brain, the researchers hypothesised that any change in nerve function may be