Importance of the Parasympathetic Nervous System for Controlling Dry Eye

Tear secretion is very unique to humans but the regulation of tear secretion has remained a mystery for many years. It has been described that the parasympathetic control and the sympathetic control work together to control tear secretion. However, we did not know which of the two is more important. Recently, we have shown that the parasympathetic nervous system in mouse model is more important than the sympathetic nervous system for tearing. In order to prevent dry eye, modern society should emphasize the importance of the parasympathetic nervous system.