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Alice Y. Matoba, M.D. and
Charles N. S. Soparkar, M.D., Ph.D.
Baylor College of Medicine
Poking at an eye will cause it to close. This is an extreme example, but it makes the point that if the eye is irritated, the eyelids close. Frequent eye irritation thus causes secondary blepharospasm (blepharospasm secondary to an external irritant).
Dry eye, defined as a deficiency of normal tear function on the surface of the eye, is a common cause of secondary blepharospasm. Dry eye increases with age and afflicts some 1 to 1.3 million people in the United States between the ages of 65 and 85. Although somewhat less common among younger individuals, dry eye may be on the increase, exacerbated by allergens, environmental pollutants, autoimmune diseases, and growing changes in hormonal levels seen across the United States in both sexes at all ages.Causes of Dry Eye:
The surface of the eye interacts with specialized tear glands to provide feedback control of tear production. Disturbance of this feedback system can lead to an unstable or insufficient tear film, resulting in chronic eye inflammation, irritation, and pain. Many medications such as antihistamines, antidepressants, and diuretics ("fluid pills" used in the treatment of high blood pressure) can worsen dry eye symptoms, as can wind, ceiling fans, air conditioning, heating, decreased humidity, and environmental allergies.
Some conditions that may cause or exacerbate dry eyes include autoimmune disorders (Sjögren Syndrome, rheumatoid arthritis), blinking problems (Parkinson's disease, Bell's palsy, myasthenia), common skin disorders (rosacea, sebaceous hyperplasia), sagging lower eyelids, and posterior blepharitis. Posterior blepharitis is characterized by inflammation of the oil glands of the eyelids that leads to a chemical destabilization of the tear film. Over time, if untreated, the inflammation leads to progressive scarring of the glands, tear production deficiency, and worsening of the blepharitis.Diagnosis:
The diagnosis of dry eye can be complicated and requires careful review of symptoms, eye examination, and perhaps some tests. People with dry eyes often experience irritation and soreness, and sometimes a feeling that there is something in their eyes. The symptoms may be exacerbated by air travel, sitting near an air conditioner vent, and prolonged visual effort, such as reading, watching TV, or working at the computer. Using artificial tears often temporarily relieves symptoms, whereas eye irritation due to other conditions, such as infections, usually will not improve with lubricating drops. Some contact lenses will worsen symptoms, whereas others improve them.
Careful evaluation of eyelid position, function, and frequency of blinking is important. The lid margins are evaluated for signs of blepharitis. The tear film is examined for the amount of the tear volume and presence of mucus or debris. The surface of the eye is evaluated for the presence of dry spots.
Diagnostic tests might include tear breakup time, a test of the stability of the tear film. Fluorescein dye is placed on the eye. With tear instability, dry spots will be observed in less than 10 seconds. Vital dyes such as rose Bengal, fluorescein, and lissamine green can be used to identify where eye surface cells have been damaged from dry eye. This finding indicates a more advanced state of dry eye.
The Schirmer test measures the amount of aqueous tear produced by the eyes. In this test, a strip of filter paper is placed at the edge of the eyelid for a standard length of time, usually five minutes, and the amount of tear volume that has soaked into the filter paper is measured. In general, a Schirmer's test reading of less than 5 mm is diagnostic of significant tear deficiency.Treatment:
Dry eye treatment is usually first managed with artificial teardrops. Many non-preserved tear substitutes are now available and are generally preferable to those with conventional preservatives. Individuals with severe tear deficiency will benefit from using long-lasting, high viscosity tear substitutes.
Recent data indicate that tear deficiency leads to inflammation of the ocular surface, so low potency corticosteroids, such as loteprednol eye drops four times a day, or topical cyclosporine drops can be prescribed to enhance the efficacy of tear replacement. Whereas topical steroids should be used sparingly because of potential complications such as cataract formation or secondary glaucoma, cyclosporine seems both safe and effective for long-term use.
Medications by mouth are also available to treat severe dry eyes, especially in people with combined dry eye and dry mouth, such as Sjögren Syndrome. Pilocarpine and cevimeline stimulate saliva production in people with dry mouth, but have a more limited effect on increasing tear production. However, these medications must be used carefully as they can produce side effects, such as excessive sweating and trouble focusing the eyes during reading.
Surgical treatment for people with tear deficiency includes closing the holes (puncta) that allow what few tears are made to drain away from the eye and into the back of the nose. The puncta may be closed using a variety of hard silicone or foam-like plugs. These plugs are semi-permanent in that they may be retained for one year or more, but are also reversible since they can be removed if the dry eye condition improves. The plugs, however, are not without complications, so permanent surgical occlusion may be an important option for some. Conditions such as eyelid malposition, poor eyelid closure, and incomplete eyelid blink are most often managed with eyelid surgery. In cases of severe dry eyes, tarsorrhaphy or partial closure of the eyelids to reduce tear evaporation from the ocular surface can be performed.
In general, significant dry eye is a chronic condition that may gradually worsen with time and requires careful monitoring and treatment by an ophthalmologist.Dry Eye and Blepharospasm:
People with benign essential blepharospasm (BEB) often have dry eyes. BEB does not cause dry eyes, but rather eye surface irritation created by the dry eye condition may result in secondary blepharospasm. It can be very difficult to distinguish what portion of a person's blepharospasm is primary (benign essential blepharospasm, caused by an intracranial dysfunction) and what part is secondary (induced by a tear film problem). Sometimes, placing a drop of topical anesthetic in the eye may provide essential information in this regard. Importantly, many treatments for primary benign essential blepharospasm can worsen dry eye symptoms, resulting in further eyelid closure. The botulinum toxins, for example, can decrease normal blinking, and normal blinking is essential to repeatedly coat the eye surface with tears. In addition, medications such as antidepressants or sedatives (benzodiazepines) can decrease tear production and blink rates, respectively.
Originally published in the Benign Essential Blepharospasm Research Foundation Newsletter, Volume 23, Number 4, pages 1, 3 (2004)Home > Related Disorders > Top of this page
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