A prolonged absence of lubrication and moisture on the surface of the eye causes dry eyes. To maintain your eyes healthy, comfortable, and seeing well, you need an adequate and regular layer of tears on the surface of the eye. The condition of having dry eyes is known as dry eye syndrome (DES), also known as keratoconjunctivitis sicca (KCS). Dry eyes can cause a variety of symptoms, ranging from minor irritation to severe inflammation. It may also result in scarring on the eye's front surface. Dry eye syndrome is a frequent ocular condition. Depending on the demographic studied, it affects 5–34 percent of persons to some degree.