What causes dry eyes?

What causes dry eyes?

The majority of patients with dry eye have chronic inflammation (swelling) in the tear glands (lacrimal glands) that line the eyelid and in the conjunctiva (the thin lining on the inside of the eyelids and the front part of the eye). Just like inflammation in a knee, lungs or liver, this chronic inflammation can permanently damage the tear gland tissue to the point that treatment becomes ineffective.

In addition to an imbalance in the tear-flow system of the eye, dry eye can be caused by the drying out of the tear film. This can be made worse by dry air created by air conditioning, heat or other environmental conditions.

Many patients also have ocular rosacea (meibomian gland dysfunction), an abnormality of the glands on the edge of the eyelid (meibomian glands) that are supposed to produce the oil to prevent evaporation of the tears. When a patient has both dry eye and ocular rosacea, not only does he or she produce too few tears, but the tears that are made evaporate too quickly.