Dry Eye Syndrome

From Wikivision

Dry Eye Syndrome (DES) or Keratoconjunctivitis sicca (KCS) is an eye disease caused by either increase in tear evaporation from the surface of the cornea or decrease in tear production by the lacrimal glands of the eye^[1]. This condition commonly has been seen in human and some animals^[2]. Dry Eye is classified into three stages of mild, moderate, and sever. In each stage this could cause discomfort, blurred vision, and even loss of vision.

Contents 1 Symptoms 2 Causes 3 Diagnosis 4 Treatments 5 References

Symptoms

Dry eyes syndromes include irritation, burning, itching, a pulling sensation, pressure behind the eye, and a feeling like something is in the eye. This condition also makes the eyes feel dry, scratchy, and gritty. Other symptoms include stinging pain, eye fatigue after short periods of reading, sensitivity to light, redness, blurry vision, and the feeling that there is a speck of dirt in the eye^[3].

Causes

The most common causes of dry eye is ageing because tear production decreases as we get older. Women get affected more than men because hormonal changes during pregnancy, menstruation, and menopause can decrease tear production. Environmental conditions also play an important role. Wind, heat, dust, air conditioning, cigarette smoke, and even hair dryers can make the eyes dry.

Not blinking enough, especially during activities such as driving, reading, watching TV, and computer use. Blinking covers the eye with a coat tear. In average, we normally blink about every 12 seconds. But a study done among those of playing computer games, shows that some people blink only once or twice in three minutes.

Wearing contact lenses can also cause dry eye. Because soft contact lenses, which float on the tear film that covers the cornea, absorb the tears in the eyes. LASIK and other refractive surgeries, in which the corneal nerves are cut during creation of a corneal flap can also cause dry eye. Because the corneal nerves stimulate tear secretion.

Dry eye can be caused by certain medications. Antihistamines, some antidepressants, birth control pills, nasal decongestants, diuretics, and the prescription acne drug Accutane can cause dry eye. In some people, the cause of dry eyes is an allergic reaction to eye drops or ointments.

Some autoimmune diseases, such as lupus, rheumatoid arthritis, and Sjögren's syndrome, can attack the tear glands and cause dry eye. Other diseases can also cause dry eye, including certain types of thyroid disease can interfere with blinking. Blepharitis, an inflammation of the eyelids, can interfere with the oil glands in the eyes. A number of studies have found that diabetics are at increased risk for the disease^[4][5].

Diagnosis

Diagnosis for dry eye syndrome can be done by the symptoms alone.

A Schirmer test also can be used by placing a strip of filter paper is at the edge of the eyelid to measure the amount of moisture bathing the eye and to determine the severity of the problem. Doctors examine the eyes with a slit lamp to determine if the eye has been damaged.

Tear protein analysis also can be used to measure the lysozyme content of tears. Lysozyme accounts for approximately 20-40% of total tear protein content^[6][7].

Treatments

Every effective treatment start with a careful diagnosis to determine the causing factors of dry eye syndrome. The main goal for any kind of treatment is to keep the eye moist.

Artificial Tears

Application of over the counter artificial tears is the most effective way to treat mild to moderate cases of dry eye syndrome. In addition to artificial tear eye drops; there are lubricant ointment or gels that could be applied into the eye at bedtime.

Environmental Control

Avoiding dry environment, or places that is smoky or dusty could drastically help dry eye prevention. Avoiding staying out in windy days or places that the air conditioner or heater is directed to the eye is also a good way to prevent dry eye. Using eye glasses outdoor and humidifier indoor especially in winter is highly recommended.

Medications

Topical cyclosporine A 0.05% ophthalmic emulsion marked as Restasis in U.S. is the latest and only medication available for chronic dry eye syndrome. Cyclosporine works by decreasing inflammation on the eye surface and increasing the healthy tears^[8].

Punctual Plugs

In moderate to severe cases where the other treatments do not prevent the dryness of the eye, punctual plugs are inserted into the tear drainage ducts to prevent loss of tears through the nose and provide more tears in the eye.

Cauterization

In this technique a hot wire is applied to the drainage area and causes the tissue to shrink. This scared tissue reduces the amount of tear drainage and make more tears available to the eye surface.

Gene Therapy

Gene therapy involves the transfer of genetic material into lacrimal epithelial cells and tissues in order to treat dry eye syndrome. This type of therapy is currently under study and focuses on development of therapeutic intervention for dry eye syndromes which are associated with lacrimal dysfunction.^[9]

References

1. Barber L, Pflugfelder S, Tauber J, Foulks G (2005). "Phase III safety evaluation of cyclosporine 0.1% ophthalmic emulsion administered twice daily to dry eye disease patients for up to 3 years.". Ophthalmology 112 (10): 1790-4. PMID 16102833.
2. Shivaram Selvam,ab Padmaja B. Thomas,b Sarah F. Hamm-Alvarez,cde Joel E. Schechter,bf Douglas Stevenson,b Austin K. Mircheff,de and Melvin D. Trousdale. Current Status of Gene Delivery and Gene Therapy in Lacrimal Gland using Viral Vectors. Adv Drug Deliv Rev. 2006 November 15; 58(11): 1243–1257. NIH
3. Sendecka M, Baryluk A, Polz-Dacewicz M (2004). "Prevalence and risk factors of dry eye syndrome". Przegl Epidemiol 58 (1): 227-33. PMID 15218664.
4. Keratoconjunctivitis, Sicca eMedicine. WebMD, Inc. (2006-04-21). Retrieved on 2008-05-07. eMedecine.
5. Keratoconjunctivitis, Sicca. The Merck Veterinary Manual. Merck & Co., Inc.. Retrieved on 2008-05-07. Merk Veterinary Manual.
6. Keratoconjunctivitis Sicca. The Merck Manual, Home Edition. Merck & Co., Inc. (2003-02-01). Retrieved on 2008-05-07. Merk Manual.
7. Dry eyes. MedlinePlus Medical Encyclopedia. U.S. National Library of Medicine (2006-10-04). Retrieved on 2008-05-07. USNLM.
8. Meadows, Michelle (May-June 2005). Dealing with Dry Eye. FDA Consumer Magazine. U.S. Food and Drug Administration. Retrieved on 2008-05-07. FDA.
9. Dry eyes. Mayo Clinic. Mayo Foundation for Medical Education and Research (2006-06-14). Retrieved on 2008-05-07. Mayo.