Keratoconjunctivitis sicca (KCS), also called dry eye syndrome (DES) or keratitis sicca,[1]is an eye disease caused by eye dryness, which, in turn, is caused by either decreased tearproduction or increased tear film evaporation. It is found in humans and some animals. KCS is the most common eye disease, affecting 5 - 6% of the population. Prevalence rises to 6 - 9.8% in postmenopausal women,[2] and as high as 34% in the elderly.[3][4] The phrase "keratoconjunctivitis sicca" is Latin, and its translation is "dry [inflammation] of the cornea andconjunctiva".