What are dry eyes?
The eye depends on the presence of a tear film to provide constant moisture and lubrication to maintain vision and comfort. Tears are a combination of:
- Water, for moisture
- Oils, for lubrication and to prevent evaporation of tear liquid
- Mucus, for even spreading of tears on the surface of the eye
- Antibodies and special proteins, for resistance to infection
These components are secreted by special glands located around the eye. When there is an imbalance or deficiency in this tear system, or when the tears evaporate too quickly, a person may experience dry eye.
When tears do not lubricate the eye enough, you may have the following in your eye:
- A gritty sensation, like a feeling of a foreign body or sand
- Redness and blurring of vision
Sometimes, a person with dry eyes will have excess tears running down the cheeks, which may seem confusing. This happens when the eye isn't getting enough lubrication. The eye sends a distress signal through the nervous system for more lubrication. In response, the eye is flooded with emergency tears.
However, these tears are mostly water and do not have the lubricating qualities or the rich makeup of normal tears. They will wash dirt away from the eye, but they will not coat the eye surface properly. In addition, because these emergency tears tend to arrive too late, the eye needs to regenerate and restore itself, and treatment is necessary.
Symptoms and Causes
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.
Management and Treatment
How are dry eyes treated?
You should discuss treatment options with an ophthalmologist or optometrist (eye doctor). In some cases, dry eye is caused by another disease or condition, like rheumatoid arthritis or systemic lupus erythematosus. If this is the case, the systemic disease should also be treated in order to relieve the dry eyes.
Here are some common treatments for dry eyes:
- Topical cyclosporine A eye drops (Restasis®): These are given twice a day in each eye to treat the underlying inflammation in the tear glands so they produce more and better quality tears. It typically takes 1 to 4 months before the cyclosporine A drops reduce symptoms and signs of dry eye. These drops have been found to be safe. The main side effect is stinging upon application, which usually gets better with continued treatment. Sometimes the doctor will also treat with corticosteroid drops for 2 weeks just before the cyclosporine A to speed up the treatment and reduce stinging caused by the cyclosporine A. The corticosteroids cannot be taken long-term due to the risk they can cause cataracts and glaucoma.
- Lifitegrast (Xiidra®): These drops are also done twice a day in each eye, to treat the underlying inflammation in the tear glands. The Food and Drug Administration (FDA) has approved Xiidra to treat both the signs and symptoms of dry eye diseases with an onset of action in as little as 2 weeks. It is the first approved drug in a new class of medication called lymphocyte function-associated antigen 1 (LFA-1) antagonists.
- Artificial teardrops and ointments: The use of artificial teardrops is a palliative (soothing) treatment that helps symptoms for a few minutes but does not treat the underlying cause of the dry eye disease. Artificial tears are available over the counter. No one drop works for everyone, so you might have to experiment to find the drop that works for you. If you have chronic (long-lasting) dry eye, it is important to use the drops even when your eyes feel fine, to keep them lubricated. If your eyes dry out while you sleep, you can use a thicker lubricant, such as an ointment, at night. If you have ocular rosacea associated with dry eye, then newer artificial tears contain lipid to help prevent tear evaporation. If you take artificial tears 4 or more times a day, you should use non-preserved artificial tears, since preservatives will likely worsen your condition.
- Temporary punctal occlusion: Sometimes it is necessary to close the ducts that drain tears off the eye. This is done via a painless procedure where a plug is inserted into the tear drain of the lower eyelid. The plug will dissolve quickly. This is a temporary procedure, done to determine whether permanent plugs will help reduce symptoms and signs.
- Permanent punctal occlusion: If temporary plugging of the tear drains works well or plugging is thought to be important for the health of the eye, then silicone plugs may be used. (Some physicians will go directly to silicone plugs without using temporary punctual occlusion.) The permanent plugs will hold tears around the eyes as long as they are in place. They can be removed. Rarely, the plugs may come out on their own or move down the tear drain. Many patients find that the plugs improve comfort and reduce the need for artificial tears.
- Surgery: If needed, the ducts that drain tears into the nose can be permanently closed to allow more tears to remain around the eye. This is done with local anesthetic on an outpatient basis. Cyclosporine A drops should always be tried for at least 6 months before permanent punctal occlusion to insure the patient doesn’t have tears running down the face (epiphora) when the dry eye inflammation is treated and the glands produce more tears.
- Autologous serum drops: In severe cases of dry eye, artificial tears made from the patient’s own serum can be prepared and given 6 to 8 times a day in both eyes. This treatment, although often effective, is expensive ($300 to $400 every 3 months) and is not covered by Medicare or insurance.
Symptoms can be greatly improved by these treatment options.
How can I improve my dry eyes at home?
On your own, you can take these steps to improve dry eye:
- Humidify the bedroom to at least 40 percent humidity when you are sleeping (when tear production is lowest). This can be measured with a humidity meter (hygrometer) on the nightstand. Humidity may be very low (less than 25 percent) during the winter when the heater is on, and this worsens the dry eye condition.
- You can take alpha omega fatty acids or fish oil or flaxseed oil orally (by mouth) to improve dry eye.
- Take frequent breaks when you are doing something that requires close concentration (such as using a computer or reading), and blink frequently.
- Take artificial tears frequently.
- Wear sunglasses when you are outside to protect your eyes from wind and sun.