Dry Eye

Every time you blink, the front surface of your eye, known as the cornea, is lubricated with tears. To help keep your eyes comfortable and your vision optimal, a thin tear film—which consists of a mucus layer, a watery layer, and a lipid (or fat) layer—coats your eyes.

Dry eye is a common disorder that occurs when the eye does not produce enough tears, when tears evaporate too quickly, or if there is an abnormality in the production of mucus or lipids normally found in the tear layer. Dry eye is more common in older adults, but can occur at any age.

Without tears to lubricate the eye, you may experience pain, redness, stinging or burning, a feeling of sand or grit in the eye, discharge, blurred vision, excess watering, and discomfort with contact use. Dry eye can make it more difficult to perform some activities, such as using a computer or reading for an extended period of time, and it can decrease tolerance for dry environments, such as the air inside an airplane.

In most cases, dry eye can be managed successfully, usually resulting in noticeably greater eye comfort and fewer dry eye symptoms. For ways to prevent dry eye, see the Table.

Causes

Dry eyes can be caused by ordinary things that increase tear evaporation, such as looking at a computer screen too long; being outside in windy, dry conditions; or just being tired. Cigarette smoke may also cause dry eyes. Other common causes of dry eye include:

• Aging. Tear production tends to decline with age. Dry eyes are common in individuals older than 50 years.
• Gender. A deficiency of tears is more common in women, especially with hormonal changes caused by pregnancy, the use of birth control pills, or menopause.
• The use of cold or allergy medicines, antidepressants, and drugs for high blood pressure; acne; birth control; and Parkinson’s disease.
• Wearing contact lenses.
• An eye injury or other problem with your eyes or eyelids.
• Diabetes.
• Thyroid disorders.
• Vitamin A deficiency.
• Sjögren’s syndrome, which includes dry eyes, mouth, and mucus membranes, and often rheumatoid arthritis or another joint disorder.
• Previous eye surgery.
• Inflammation that causes tear gland damage.

Symptoms

If you have dry eyes, you may experience a dry, gritty, scratchy, or filmy feeling; burning or itching; redness of the eyes; blurred vision; foreign body sensation; and light sensitivity. You may also have strained or tired eyes after reading, even for short periods of time. If you wear contacts, they will likely feel uncomfortable. Having dry eyes for a while can lead to tiny abrasions on the surface of your eyes.

You may also notice episodes of excessive tearing followed by very dry eye periods. This is because the eyes produce a large amount of tears at once to try to get moist and comfortable again. Unfortunately, because tear ducts can only handle so many tears at any one time, the excess tears pour down the cheeks. The whole process may repeat itself, too.

Who Is Likely to Develop Dry Eye?

Elderly individuals frequently experience dryness of the eyes more often. However, dry eye can occur at any age. Nearly 5 million Americans 50 years and older are estimated to have dry eye. Of these, more than 3 million are women and more than 1.5 million are men. Tens of millions more have less severe symptoms. Dry eye is more common after menopause. In addition, women who experience menopause prematurely are more likely to have eye surface damage from dry eye.

Diagnosis

During a comprehensive eye exam, the ophthalmologist will most likely be able to diagnose dry eye based on your symptoms, general health problems, medications, and environmental factors that may be contributing to the dry eye problem. As part of the eye examination, the following tests may be performed:

• Measuring the volume of your tears. Your health care provider (HCP) may measure your tear production using the Schirmer test. In this test, your HCP will place the end of a special paper strip inside the lower eyelid of each eye. After 5 minutes, your HCP measures the amount of strip soaked by your tears.
• Determining the quality of your tears. Other tests use special dyes in eyedrops to determine the surface condition of your eyes. Your HCP looks for staining patterns on the corneas and measures how long it takes before your tears evaporate.

Treatment

Depending on the causes of dry eye, your HCP may use various approaches to relieve the symptoms.

Adding Tears

For occasional or mild dry eye symptoms, OTC eyedrops (artificial tears) used regularly may provide relief. Preservative-free artificial tears are preferred, as they cause less irritation. Wearing glasses or sunglasses that fit close to the face (wraparound shades) or that have side shields can help slow tear evaporation from the eye surfaces. An indoor air cleaner to filter dust and other particles can help prevent dry eyes, as can a humidifier by adding moisture to the air, avoiding dry conditions, and allowing your eyes to rest when performing activities that require you to use your eyes for long periods of time. Instill lubricating eyedrops before performing such tasks.

Treating the Underlying Cause

In some cases, treating an underlying health issue can help clear up the signs and symptoms of dry eyes. Underlying causes of dry eye, such as Sjögren’s syndrome or lacrimal and meibomian gland dysfunction, can be treated and, in turn, relieve dry eyes. If a medication is causing your dry eyes, your HCP may recommend a different medication that does not cause that adverse effect.

Medications

Prescription medications used to treat dry eyes include:

• Cyclosporine. This anti-inflammatory medication is the only prescription drug available to treat dry eye. It decreases corneal damage, increases basic tear production, and reduces symptoms of dry eye. It may take 3 to 6 months of twice-daily dosages for the medication to work. In cases of severe dry eye, short-term use of corticosteroid eyedrops that decrease inflammation is required.
• An artificial tear insert such as Lacrisert may be an option for individuals with moderate to severe dry eye symptoms. Tear inserts are inserted between the lower eyelid and the eyeball, and the cellulose within the insert acts to stabilize and thicken the film of tears over the eyes.

Procedures

Procedures that may be used to treat dry eyes include:

• Partially or completely closing the tear ducts
• Using special contact lenses
• Unblocking oil glands
• Using light therapy and eyelid massage

Beth is a clinical pharmacist and medical editor residing in Northern California.

Resources

• Facts about dry eye. National Eye Institute website. nei.nih.gov/health/dryeye/dryeye. Accessed March 24, 2016.
• Dry eyes. Medline Plus website. nlm.nih .gov/medlineplus/ency/article/003087.htm. Accessed March 24, 2016.
• Dry eyes. Mayo Clinic website. mayoclinic .org/diseases-conditions/dry-eyes/basics/definition/ con-20024129. Accessed March 24, 2016.
• Dry eye. American Optometric Association website. aoa.org/patients-and-public/eye-andvision- problems/glossary-of-eye-and-visionconditions/ dry-eye?sso=y. Accessed March 24, 2016.