What is dry eye?Dry eye occurs when the eye does not produce tears properly, or when the tears are not of the correct consistency and evaporate too quickly. In addition, inflammation of the surface of the eye may occur along with dry eye. If left untreated, this condition can lead to pain, ulcers, or scars on the cornea, and some loss of vision. However, permanent loss of vision from dry eye is uncommon. Other names for dry eye include dry eye syndrome, keratoconjunctivitis sicca (KCS), dysfunctional tear syndrome, lacrimal keratoconjunctivitis, evaporative tear deficiency, aqueous tear deficiency, and LASIK-induced neurotrophic epitheliopathy (LNE).
What are tears, and how do they relate to dry eye?Tears, made by the lacrimal gland, are necessary for overall eye health and clear vision. Tears bathe the surface of the eye, keeping it moist, and wash away dust and debris. They also help protect the eye from bacterial and other types of infections. Tears are composed of three major components:
- Outer, oily, lipid layer produced by the meibomian glands
- Middle, watery, lacrimal layer produced by the lacrimal glands
- Inner, mucous or mucin layer produced by goblet cells located within a thin transparent layer over the white part of the eye and covering the inner surface of the eyelids.
What are common symptoms?Common symptoms include blurred or variable vision, sensitivity to light, pain or feelings of dryness, burning and/or stinging sensations.
What causes dry eye?Dry eye can be caused by:
- Side effects of certain drugs
- Air conditioning, heating systems, or ceiling fans
- Dry environments
- Improper contact lens use, fit, and solutions
- Computer use
- Eyelid disease or structural problems with the eyelids
- Cigarette smoke