The continuous production and drainage of tears is important to the eye's
health. Tears keep the eye moist, help wounds heal, and protect against
eye infection. In people with dry eye, the eye produces fewer or less quality
tears and is unable to keep its surface lubricated and comfortable.
The tear film consists of three layers--an outer, oily (lipid) layer that
keeps tears from evaporating too quickly and helps tears remain on the eye;
a middle (aqueous) layer that nourishes the cornea and conjunctiva; and
a bottom (mucin) layer that helps to spread the aqueous layer across the
eye to ensure that the eye remains wet. As we age, the eyes usually produce
fewer tears. Also, in some cases, the lipid and mucin layers produced by
the eye are of such poor quality that tears cannot remain in the eye long
enough to keep the eye sufficiently lubricated.
Dry eye can occur in climates with dry air, as well as with the use of some
drugs, including antihistamines, nasal decongestants, tranquilizers, and
anti-depressant drugs. People with dry eye should let their health care
providers know all the medications they are taking, since some of them may
intensify dry eye symptoms.
People with connective tissue diseases, such as rheumatoid arthritis,
can also develop dry eye. It is important to note that dry eye is sometimes
a symptom of Sjögren's syndrome, a disease that attacks the body's
lubricating glands, such as the tear and salivary glands. A complete physical
examination may diagnose any underlying diseases.
The main symptom of dry eye is usually a scratchy or sandy feeling as
if something is in the eye. Other symptoms may include stinging or burning
of the eye; episodes of excess tearing that follow periods of very dry
sensation; a stringy discharge from the eye; and pain and redness of the
eye. Sometimes people with dry eye experience heaviness of the eyelids
or blurred, changing, or decreased vision, although loss of vision is
Dry eye is more common in women, especially after menopause. Surprisingly,
some people with dry eye may have tears that run down their cheeks. This
is because the eye may be producing less of the lipid and mucin layers
of the tear film, which help keep tears in the eye. When this happens,
tears do not stay in the eye long enough to thoroughly moisten it.
Artificial tears, which lubricate the eye, are the principal treatment
for dry eye. They are available over-the-counter as eye drops. Sterile
ointments are sometimes used at night to help prevent the eye from drying.
Using humidifiers, wearing wrap-around glasses when outside, and avoiding
outside windy and dry conditions may bring relief. For people with severe
cases of dry eye, temporary or permanent closure of the tear drain (small
openings at the inner corner of the eyelids where tears drain from the
eye) may be helpful.