In some cases, the dryness is so severe that ulcers form or cloudiness appears on the cornea, distorting vision. Without this fluid, the eye is left unprotected. A number of factors cause the tear glands to slow or even halt production. For many, air-conditioning can dry out the eyes. Medications such as antihistamines and some anti-depressants can do the same.
Hormonal changes brought on by menopause can cause dry eyes in older women.
Others susceptible to dry eyes include people suffering from diseases such as rheumatoid arthritis, lupus or neurological disorders and those who wear contact lenses. Pflugfelder noted that some patients who undergo laser surgery to correct vision have reported dryness in their eyes. Although most people with dry eyes can be treated with common eye drops, many don't respond. Anti-inflammatory agents such as cyclosporin and antibiotics like tetracycline have been used effectively. But Pflugfelder said even those drugs don't work on everyone.