Caffeine can increase tear production and may someday be a treatment for dry eye, a new study shows. The study was small, including only 78 people with normal tear production, says researcher Reiko Arita, MD, PhD, a clinical researcher at the University of Tokyo School of Medicine and an associate professor at Keio University in Japan. She also found those with certain genetic variations had more tears in their response to caffeine. These variations differ among ethnic groups."However,” she says, “I suppose a third to a half of the population has the possibility to respond to caffeine.’' The study is published in the journal Ophthalmology.
