Dry eye syndrome (also referred to as: Keratitis Sicca) is a common condition thought to affect approximately 60 million Americans. In some instances, it is characterized by dry, irritated eyes due to a lack of lubricating tears due to an imbalance between tear production and tear volume drainage via the nasolacrimal ducts (NLD). It can also be a result of excessively watery eyes due to tears lacking the proper balance of mucous, water and oil to coat the eyes properly.
The tear film is made up of a mucous layer against the eye, a middle aqueous (water) layer, and an outer lipid (oily) layer. All three components are critical to a normal tear film. If any of the three layers of the tear film are deficient, the eye may suffer symptoms of dry eye.
There are two types of tears: lubricating and reflex. Lubricating tears protect the eyes against the elements. They are produced in a steady flow throughout the day and spread across the eye by the blink reflex.
Reflex tears flood the eye suddenly whenever the eye is irritated. They can flow to such a degree that tears roll down the cheek. This excessive watering may occur when the eyes are irritated due to smoke, smog, irritants like onions, or when the eyes lack proper protection from lubricating tears.
Symptoms of dry eyes may include burning, stinging, redness of the eyes and tearing. The tearing seems paradoxical at first, but is explained by the fact that an underlying dry eye may become irritated, perhaps sending a "signal" for increased tear production to "flush-out" the eye. This response is physiologically equivalent to the presence of a foreign body, such as a hair or a pebble of sand in the eye. Vision can be blurred.
Tearing that becomes symptomatic usually occurs in conditions that more rapidly evaporate tears from the eye, such as being outdoors in the wind. Heat, low humidity, and the presence of smoke may compound the problem. As mentioned, in most cases the cause of dry eye syndrome is unknown. However, certain other disease states as well as medications may be associated with dry eye.
Patients with rheumatoid arthritis and those individuals who take antihistamines (for allergic symptoms) probably represent the largest groups of patients who present with a known cause for dry eye syndrome. Patients who present with dry eye and dry mouth may have a condition known as Sjogren's syndrome.
Dry eye syndrome can usually be diagnosed by ophthalmologists with the patients' history alone, though the exam is confirmatory. On exam, the patient typically shows a reduced tear volume and rapid tear break-up time (the time for dry spots to occur on the cornea. Placement of fluorescein dye in the tear film allows the tear film to be better visualized. Some ophthalmologists will test tear production using specially prepared "tear-strips".
The severity of dry eye syndrome generally dictates the course of treatment. In most cases, the patient is recommended to use artificial tear drops or ointment in the eye on a regular basis, perhaps 4 times a day. If the condition is to be treated with artificial tears chronically, many ophthalmologists will recommend non-preserved artificial tears.
Although most of these products can be obtained without prescription, it is highly advisable to consult with your eye doctor. Excessive or prolonged use of artificial tears can disrupt the eyes natural production of tears, leading to further aggravation of the condition instead of providing desired relief.
A humidifier in the home, especially next to the bed at night has been found to be particularly helpful for many patients. Due to "hard" tap water in most areas, however, distilled water is usually required. "Hard water" in many areas will create an airborne mineral dust, which may make the humidifier less effective for this intended purpose.
For those patients who fail to improve with the above treatment, or have a severe dry eye presentation, occlusion of the puncta (tear drainage openings) located in each of the four lids may be completed. This usually entails simple insertion of a punctal plug into one or more of the tear drainage duct openings. This procedure is quick, simple, and often very effective in helping to relieve dry eye symptoms, even in the most severe cases.
The tiny plugs, usually made of silicone or other inert material, can be inserted with little or no discomfort and are rarely felt by the patient afterwards. In the unusual case that the patient then has too many tears, the plug can just as easily be removed. Some ophthalmologists choose to avoid plugs and elect to close the puncta (tear duct openings) with cautery. This is also simple and effective, although the puncta may spontaneously re-open many months or years later.
There continues to be significant clinical study in the field of dry eye syndrome. Two areas of research on the forefront of dry eye are the use topical androgens and cyclosporin. Androgens appear to play a complex but important role in tear production and studies are underway to determine if topical application of certain of these hormones may improve tear production and symptoms.
Cyclosporin, an immunomodulating agent used in organ transplantation, is presently in FDA trials for patients with dry eye syndrome. The anti-inflammatory effect of topical cyclosporin may improve overall tear function and/or production.
Other treatments available for dry eye syndrome include the following:
Note: Many patients with Progressive Supranuclear Palsy develop dry eye syndrome. Left unattended it can cause damage and roughness to the surface of the eyeball. The artificial tears mentioned here are not the same as common eye drops such as "Murine".
If this is a problem it is always better to consult an eye professional for advice and treatment.
