Dry eye disease (DED), also known as dry eye syndrome or dysfunctional tear syndrome, is a condition that involves the tears and the surface of your eyes. Your eye constantly produces tears which move across the surface of your eye, keeping it moist. People with DED either don't produce enough tears or the tears they do produce evaporate off the eye surface too quickly to keep the eye moist. Some people with DED have both issues. Because of this, your eyes can feel dry and irritated.
DED is one of the most common conditions seen by optometrists. It affects up to 30% of those over the age of 50. Unfortunately, it is often underdiagnosed because many people believe that having dry eyes is a normal part of aging and that nothing can be done to prevent or treat it.