Japanese researchers have found that caffeine treats xerophthalmia

In recent years, studies have shown that drinking coffee can reduce the risk of cancer, diabetes, gallstones and Parkinson's disease. Now, Japanese researchers have found that caffeine can also treat dry eyes.

Xerophthalmia can cause pain and tingling, and some patients with severe xerophthalmia may even impair their eyesight. Researchers at the University of Tokyo School of Medicine in Japan studied 78 patients with xerophthalmia. In the first phase, half of the patients were given caffeine pills and the other half were given a placebo.

In the second stage, the two groups are exchanged. No one knows they're on caffeine. Six days before the study, the participants stopped eating any caffeinated food or other drugs to reduce the variable.

The results showed that patients' tears increased significantly as long as they took caffeinated pills. The researchers say the focus is not only on caffeine, but also on a person's ability to metabolize caffeine.

The researchers found that if there were two sets of variations in a patient's DNA, the body's ability to metabolize caffeine changed. After consuming caffeine, the body produces more tears. Not only tears, but by the same principle, caffeine also increases saliva and digestive juice secretion.