Dry Eye Can be Debilitating

By Paddy Kamen

Is angina a more serious disease than dry eye? The majority of people would probably answer yes. But a recent survey showed that people with moderate to severe dry eye experience as much impact from their disease as those who suffer from the same levels of angina or other similar medical conditions.

In fact, although for some people dry eye is just an occasional feeling of mild discomfort associated with environmental conditions, for others it can be a chronic medical condition that if left untreated may cause serious damage. Chronic dry eye, also referred to as dry eye syndrome or keratonconjunctivitis sicca, can cause corneal changes that may predispose those with the disorder to corneal ulcerations, which can permanently impair vision.

The group of disorders known as dry eye is characterized by insufficient tear production, excessive tear evaporation or abnormal tear composition. There is no definitive test for the condition and certain other disorders mimic its symptoms, making diagnosis difficult.

Symptoms of dry eye can vary greatly from one patient to the next. Common symptoms include: irritation, tearing, burning, feelings of stinging, discomfort, dryness, grittiness, sensation of a foreign body, itching, photophobia, blurry vision, contact lens intolerance, redness, mucous discharge, and increased frequency of blinking. Symptoms often fluctuate throughout the day, usually becoming worse as the day goes on.

The prevalence of dry eye is difficult to precisely determine because data-gathering methods and diagnostic criteria vary, diagnostic tests cannot definitively confirm or rule it out, and research is sparse. However, U.S. studies show that nearly 40 per cent of that population is affected by dry eye.

Risk Factors

There are many possible causes of dry eye and several contributing factors have been identified. It is now known that an inflammatory process in the eye tissues is an important underlying cause, which may be brought on by various hormonal or neuronal factors. Dry eye also is associated with certain autoimmune disorders such as rheumatoid arthritis and Sjögren’s syndrome (1), or lupus. Dry eye due to deficient tear production is often designated as “Sjögren’s” or “non-Sjögren’s.” Non-Sjögren’s tear-deficient dry eye can be precipitated by exposure to allergens and irritants like dust or smoke, and certain systemic medications such as diuretics, antihistamines, anticholinergics, antidepressants and retinoids. Often the term Sjögren’s is used to describe any aqueous tear deficiency.

A paper by Dr. Marguerite McDonald, clinical professor of ophthalmology at Tulane University School of Medicine (2), states that LASIK therapy can cause
post-operative damage to corneal nerves and thus induce dry eye.

Dry eye due to increased evaporative loss can be caused by: Blepharitis (3), including meibomian gland malfunction (these glands produce the lipid layer of the tear film, which normally slows tear evaporation), exposure to wind or drafts (e.g., outdoors or indoors from a vent or a hair dryer), contact lenses, failure to spread the tear film over the eye due to abnormal blinking or eye/eyelid anatomy, and environmental causes including reduced humidity, air conditioning or heating.

Advanced age is another risk factor. We can therefore expect the incidence of dry eye to increase as baby boomers age. Why does aging give rise to a higher incidence of dry eye? As adults get older, the quantity and quality of their tear production decrease. This may be due, in part, to decreased production of androgens. One current theory of tear-deficient dry eye development involves inflammation as an underlying cause. Immune cells called regulatory T-cells help keep inflammation in check. Androgens support regulatory T-cells. Therefore, a decrease in androgen associated with aging or menopause results in a decrease in regulatory T-cell activity, ensuing an increased inflammation, which can lead to tear-deficient dry eye.

Dry eye is twice as common in women than men and estimated to affect more than 3.2 million American women over age 50. Menopause increases the risk of dry eye, probably because of the confluent effects of aging, decreased androgen production, and diminution of estrogen production (4).

Quality of Life Issues

People who experience dry eye find it has a negative impact on their quality of life, interfering with vision-related activities including reading, professional work, contact lens wear, computer use and night driving. Studies confirm that many patients make significant changes to their daily lives to manage their symptoms.
Yet many people aren’t aware of the signs and symptoms of dry eye, or don’t bother reporting them to their doctor.

The American Academy of Ophthalmology says that those with very mild and infrequent symptoms of dry eye will likely need no treatment. If, however, the symptoms cause discomfort, preserved artificial tears available over the counter may provide adequate relief. If they don’t, or if the person is using artificial tears three or more times a day, a visit to the doctor and ophthalmologist or optometrist is recommended. Diagnosis requires assessment of a patient’s history and symptoms, a physical examination, an eye examination and various special eye tests.

Treatment Options

Until recently, treatment options for dry eye were largely limited to temporary symptom relief, such as artificial tears, and strategies to modify exacerbating lifestyle and environmental factors. This has changed during the last decade and there is new hope for dry eye sufferers. The complex pathophysiology of dry eye is now better understood and this has led to the development of treatments that target the underlying cause of the disease to restore ocular health.

The primary example of such a therapy is a prescription eye drop (cyclosporine ophthalmic emulsion) containing cyclosporine A (CsA), a substance that suppresses inflammation due to activity of certain immune cells and helps the eyes increase natural tear production. Currently, this is the only prescription therapy for patients with dry eye due to deficient tear production resulting from ocular inflammation. Over-the-counter products are often used to treat this condition as well. Surgical treatments, such as closure of the tear ducts with plugs or cauterization, also are available for patients who do not respond adequately to medical approaches.

There is little doubt that dry eye affects the quality of life and health of millions of North Americans each year. The costs of dry eye may be reflected in lost days of work, the need to purchase over the counter remedies, and in chronic cases the need for surgical intervention. Hopefully a greater focus on research into dry eye will lead to a better quality of life for those who suffer from the chronic form of this disorder.

With notes from: Is There a Dry Eye in the House: A Science Writers Guide to Dry Eye, The American Academy of Ophthalmology, 2006. Used with permission.

1 Sjögren’s syndrome: Sjögren's ("SHOW-grins") syndrome is a chronic disease in which white blood cells attack the moisture-producing glands. The hallmark symptoms are dry eyes and dry mouth, but it is a systemic disease, affecting many organs and may cause fatigue.

2 LASIK and Dry Eye, Marguerite McDonald, MD, FACS, from PROCEEDINGS™, State of the Art Management of Chronic Dry Eye, March 2006.

3 Blepharitis: inflammation of the eyelids, particularly at the lid margins.

4 Janine Smith, MD, Deputy Clinical Director, National Eye Institute, from PROCEEDINGS™, State of the Art Management of Chronic Dry Eye, March 2006.