An estimated 12 million Americans have dry eyes. This condition is the inability to produce enough tears to keep the surface of the eyes lubricated and comfortable.
Tears are made by tissue in the lacrimal glands. The major lacrimal glands lie under the skin and extend into the eye socket. Tears reach the surface of the eye via small openings from the gland. Tears drain from the eye’s surface by flowing into other tiny openings (lacrimal puncta), then into canals in the eyelids (lacrimal ducts), into a small pouch (lacrimal sac) and finally into the nose.
Normally, blinking helps the eyelids spread a tear film over the eye. If blinking is prevented, dry spots develop on the surface of the eye and vision decreases.
The continuous production and drainage of tears is very important. Tears keep the eyes moist, help ocular wounds heal and protect against eye infections. Persons with dry eyes are at greater risk of developing eye infections.
What causes dry eyes?
Dry eyes occur:
- With age. Dry eyes are more common in women, especially after menopause.
- With the use of some drugs, including antihistamines, nasal decongestants and sedatives.
- Sometimes after eye surgery.
- In some persons with malpositioned lower eyelids.
- Infrequently after irradiation to the eye.
- In climates with dry air.
Sometimes with vitamin A deficiency or after a chemical burn to the eye.
In dry eye syndromes, called keratoconjunctivitis sicca, where both eyes are usually affected, causing dryness, redness, swelling, itching and burning and often reduced vision.
In autoimmune diseases such as Sjugren’s syndrome. In connective tissue diseases such as rheumatoid arthritis.
What are the symptoms of dry eyes?
The main symptom of dry eyes is usually a scratchy or sandy feeling that something is in the eyes.
Other symptoms may include:
- Stinging, burning and itching of the eyes.
- Episodes of excess tearing that follow periods of very dry sensations.
- A stringy discharge from the eyes.
- Heaviness of the eyelids.
- Pain and redness of the eyes.
Blurred, changing or decreased vision. Loss of vision usually is not severe.
How are dry eyes diagnosed?
The patient’s historical information often gives the most reliable clues to the diagnosis of dry eyes. A careful examination of all the eye tissues usually provides more documentation for making a diagnosis. AIM, a number of tests may help confirm the diagnosis.
The main test for dry eyes is the schirmer test. This test involves placing a strip of filter paper over part of the eye (conjunctival sac) for up to five minutes. Less than the normal amount of wetting, on repeated examinations, indicates decreased tear production. Unfortunately, this test misses detecting many patients with dry eyes. Other tests should also be done before ruling out a diagnosis of dry eyes.
Other diagnostic tests include applying a drop of special dye (rose Bengal stain) onto the eye. If there is a tear deficiency, the dye forms a characteristic pattern on the surface of the eye.
What treatments help dry eyes?
The main goal in the treatment of dry eyes is relief of symptoms. Usually this is achieved with artificial tears. These tear substitutes lubricate and wet the eyes. They are available over-the-counter as eye drops. Since artificial tears have short-term effects, they need to be applied often.
There are many brands of artificial tears on the market, and you may need to try several kinds to find the one that works best for you. Sometimes combinations of different artificial tears are most helpful. Some types have preservatives, which may trigger allergic reactions with long-term use.
Sterile ointments containing petrolatum are sometimes used at night to help lubricate and prevent the eye from drying. However, they may irritate some people’s eyes. These ointments usually do not require a prescription.
Other approaches to increasing moisture for the surface of the eye are available. There are different types of “inserts” that slowly dissolve in the eye and release artificial tears. These inserts are not suitable for everyone and usually require a prescription.
Preventing tears from evaporating also may help dry eyes. Using a humidifier in winter to add moisture to the air may be helpful. AIM moisture chamber glasses are available, which have a tight-fitting plastic shield on the sides to keep moisture inside.
In severe cases of dry eyes, if artificial tears do not control the symptoms, other forms of treatment may be needed. One method is closing the opening to the lacrimal ducts to prevent drainage of tears from the eyes. This involves cauterizing the tissue (using heat or electric current), laser treatment or surgery. A possible complication of closing the tear ducts is an overflow of tears. Thus, some eye surgeons first close or plug the tear ducts temporarily to test how effective this procedure would be.
When a malposition of the lower eyelids causes dry eyes, eyelid surgery may help the dryness.
For drug-induced dry eyes, stopping the medication sometimes relieves the symptoms.
No cure exists currently for the dry eye syndrome. Therefore, treatment with artificial tears is a long term process. The severity of the condition, however, often fluctuates and may improve. A major part of treatment also involves preventing the complications of eye infections.
Research at the UIC Eye Center is trying to find the best methods of treatment for dry eyes. Investigators are testing different types of artificial tears as well as chemicals that may stimulate tear secretion. They are also testing immunologic-mediating drugs that may decrease the dry eye complications in some diseases. Additionally, our researchers are studying what causes dry eye conditions and are developing new medical and surgical treatments.