Experts attribute the causes of dry eyes to several factors, including hormones, problems with tear production due to a medical condition, age, damage to the tear glands and even some types of eye surgery. Dry eyes can also develop from secondary conditions, such as environmental triggers, problems with the eyelids and even some medications, say experts at the Mayo Clinic. Additionally, some people do not naturally produce enough tears to lubricate their eyes, and for others, the source of dry eyes comes from improper composition of tear ingredients.
Regardless of dry eye cause, all tears form from the same basic elements. Human eyes require a precise balance of water, fatty oils and mucus to have sufficient lubrication, states Mayo Clinic.
Some people simply do not produce enough of one or more ingredient, which in turn produces dry eyes. Insufficient amounts of oil production can stem from clogged meibomian glands, which secrete oil onto the surface of the eye, or from oil glands that produce insufficient amounts of oil. Glands that secrete too little water create discharge, while insufficient mucus production appears as dry spots in the eyes.
Dry eyes appear more often in people older than age 50 and in menopausal women. They might also result from a temporary condition, such as exposure to wind, dry air or straining the eyes by looking at a screen for extended periods of time.