Tears, made by the lacrimal gland, are necessary for overall eye health and clear vision. They also help protect the eye from bacterial and other types of infections. Tears are constantly produced to bathe, nourish, and protect the eye surface. They are also produced in response to emergencies, such as a particle of dust in the eye, an infection or irritation of the eye, or an onset of strong emotions. When the lacrimal glands fail to produce sufficient tears, dry eye can result. Any disease process that alters the components of tears can make them unhealthy and result in 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. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane. 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).
Symptoms
Dry eye symptoms may include any of the following:
- stinging or burning of the eye;
- a sandy or gritty feeling as if something is in the eye;
- episodes of excess tears following very dry eye periods;
- a stringy discharge from the eye;
- pain and redness of the eye;
- episodes of blurred vision;
- heavy eyelids;
- inability to cry when emotionally stressed;
- uncomfortable contact lenses;
- decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention;
- eye fatigue.