What is dry eye?
If you have ever experienced stinging or burning of the eye, a sandy or gritty feeling in the eye, episodes of excess tearing, pain and redness of the eye, episodes of blurred vision, inability to cry when emotionally stressed, uncomfortable contact lenses, or discomfort associated with computer use, you may have experienced dry eye symptoms.
There are many reasons why people experience dry eye. Dry eye can occur when the eye does not produce enough tears, or when the tears are not of the correct consistency and evaporate too quickly. Inflammation of the surface of the eye can also be a cause of dryness.
Tears and their association with dry eye
Tears, produced by the lacrimal and accessory tear glands, are necessary for the overall health of the eye and clear vision. The tears bathe the surface of the eye in order to keep it moist and help to wash away dust and debris and protect the eye from infection.
Tears are composed of three major components, an outer, oily or lipid layer, a central, watery or aqueous layer and an inner mucin or mucous layer. The tears contain proteins, electrolytes and vitamins that are important to maintain the health of the outer surface of the eye.
Tears are constantly produced to bathe, nourish, and protect the ocular surface. They are also produced in response to emergencies, such as a particle of dust in the eye, an infection or irritation of the eye, or the onset of strong emotions. When the lacrimal and accessory glands fail to produce sufficient tears or tears with the correct balance of components, dry eye can result.
How is dry eye treated?
Depending on the underlying causes of dry eye, your optometrist may use different treatment options to relieve your symptoms.
Artificial tears, gels, and ointments are the first line of therapy. They offer temporary relief and provide an important replacement of naturally produced tears.
Wearing glasses or sunglasses that fit close to the face or that have side shields, when you are outside, can help slow down tear evaporation from the surface of the eye. Indoors, a humidifier may also help by adding moisture to the air.
If your dry eye is due to an underlying ocular or systemic disease or the medications to treat these conditions, more comprehensive assessments may be required. Your optometrist or physician may also recommend switching to another medication which does not have an association with dry eyes.
In more severe cases of dry eye, a short course of treatment with steroid eye drops or long term therapy with cyclosporine eye drops may be indicated. Another treatment option is to temporarily or permanently block the tear drainage openings at the inner corners of the eyelids, known as the puncta. Punctal plugs, can be inserted painlessly by an optometrist. In some cases, surgical intervention with cautery of the puncta is recommended to permanently close the drainage holes. These procedures help retain any tears, which are produced by the tear glands, on the eye.
Supplements or dietary sources of omega-3 fatty acids, especially DHA and EPA, may also decrease symptoms of irritation associated with dry eyes. The use and dosage of nutritional supplements and vitamins should be discussed with your optometrist.
If contact lens wear is the main cause of symptoms, your optometrist may recommend another type of contact lens, or reducing wearing time of your lenses. Contact lens re-wetting drops or a change in solutions may also help. In the case of severe dry eye, your optometrist may advise you not to wear contact lenses at all.