The nervous system enables a person to blink to prevent harmful substances, like smoke from getting in the eyes. During the normal course of a day, a person blinks an average of 15 times a minute to keep the eyes healthy.
The lacrimal, or tear, gland provides lubricating fluid for the eyes. The eyelid moves fluid from the lacrimal gland and across the eye. Blinking also provides the eyes with protection from foreign objects.
When the eye becomes irritated, the lacrimal gland produces extra tears to wash out impurities. Excess fluid drains through the tear ducts and canal into the nasal cavity. An abundance of tears draining through the nasal cavity may cause the nose to run and a person to sniffle.
Review Date 9/7/2021
Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.