Cold Weather Can Dry The Eyes
The surface of the eye requires a healthy tear film to provide the smooth optical surface needed for clear vision. A person who has reduced tear secretion may suffer from the symptoms of dry eyes, which include blurred vision, scratchiness, excess mucus production, burning and excess irritation from smoke. Since the number of times we blink per minute drops when we concentrate, patients often complain of tearing and blurring while reading, using the computer or watching television.
Patients with dry eyes can be severely handicapped by the condition and may find it difficult to obtain lasting relief. Surprisingly, one of the most common symptoms of dry eyes is excess tearing. The reason for this paradox is that, in response to a decreased baseline level of tear production, there are excess tears secreted by the lacrimal gland in response to the irritation of dryness. This gush of tears (similar to the increase seen with crying) referred to as reflex tearing, simply runs down the cheek but does little to maintain a lasting level of lubrication.
Our tear film is composed of three layers. The outermost layer is an oily layer produced by glands in our eyelids called meibomian (my-bow-me-an) glands. This layer helps prevent tear evaporation. The middle layer is an aqueous or watery layer produced by tiny glands scattered over the white of the eye. This watery layer makes up most of what we ordinarily think of as tears. The large lacrimal gland, which produces the tears of emotion and irritation, secretes this type of tear. The innermost layer is made of a slimy mucus which coats the eyeball surface and helps the tears coat the eye uniformly. Without the mucus, the tears would bead up on the surface of the eye like rain on a freshly waxed car. All three layers must be present in the appropriate proportion for the eye to be properly lubricated.
Our baseline tear production normally decreases as we age. However, women are much more commonly affected than men. The hormonal changes associated with menopause make women especially vulnerable to developing dry eyes. Dry eyes can be associated with rheumatoid arthritis. In fact, the triad of arthritis, dry mouth and dry eyes is referred to as Sjogren's Syndrome. Additionally, certain drugs, such as antidepressants and antihistamines, can aggravate or even initiate dry eye symptoms.
Dry eyes are treated initially with topical tear supplements, instilled as needed or on a scheduled interval. Sometimes tear ointments are required at bedtime. Wearing wrap-around glasses can reduce the evaporation of tears making the eyes more comfortable. Air conditioning and cold weather dehydrate the air and frequently worsen dry eye symptoms. A room humidifier can often provide some relief. Patients sometimes require blockage of their tear drainage ducts, which allows the tears to remain in the eye for a longer period of time. This technique, called punctal occlusion, has been very successful.
A new medication to treat dry eyes, known as Restasis, has been shown to be very beneficial in helping the surface of the eye re-establish a normal healthy tear film. This prescription medication has become widely used in the management of dry eye syndrome.
