Dry Eye
Introduction Dry eye (keratoconjunctivitis sicca) is a common problem, particularly in elderly . It causes varying degrees of discomfort. Pathophysiology The tear film is needed to maintain a healthy eye surface and for enabling clear vision. Tears are made up of a complex mixture of water, salts, lipids, proteins and mucus. The lipids, or oily component, surround the tear film and help to prevent evaporation of the water. The mucous component helps spread the tear film evenly over the surface of the eye. Historically, dry eye disease (DED) has been classified into 2 general groups: Aqueous deficient DED Decreased tear production due to Sjogren's syndrome, older age and diabetes mellitus . Evaporative DED Increased evaporative loss from the ocular surface due to meibomian gland dysfunction, structural abnormalities of eyelid position, decreased blink function, topical medicated or preserved eye drop use, chronic contact lens wear and ocular allergy syndrome. However, it is now b...