What is dry eye syndrome and how is it treated?
Dry eyes can result either from decreased tear production or too much evaporation of the tears from blepharitis or exposure. Blepharitis is inflammation of the eyelids, where the oily coating of the tears is produced. Exposure occurs when the eyes do not close properly. The tear film is composed of three main layers, like a sandwich. The outer layer, called the lipid or oily layer, is produced by the meibomian glands in the eyelids. The middle layer, the aqueous layer, is produced by the tear (lacrimal) glands. The inner layer, the mucin layer, is produced by cells in the conjunctiva. If anything is wrong with any layer of the sandwich, patients can have symptoms of dry eye. Decreased tear production, known as aqueous tear deficiency, has the technical name of keratoconjunctivitis sicca. There are many reasons for this problem including aging and certain medications, but often the cause is unknown. Sjogren’s syndrome – dry eye and dry mouth – can be either primary (no known systemic di
