Kelly Kinney Nichols, OD, MS
Dry eye syndrome is a commonly diagnosed clinical disorder of the front surface of the eye characterized by dry, irritated, stinging eyes. While the mild to moderate cases rarely cause sight damage, the disease does affect a large portion of the population. Current estimates indicate that over 10 million people in the United States suffer from dry eye syndrome. Recent studies in Canada, Australia, and the United States have shown that approximately one in four people report experiencing dry eye symptoms, while one in 225 report severe dry eye symptoms. These findings indicate dry eye is one of the most common disorders of the front of the eye encountered by eye care professionals throughout the world.
Dry eye syndrome is also more prevalent in women and in the elderly. In a small town in Maryland, 10.5% of adults over the age of 65 years routinely purchase and use lubricant eye drops to relieve dry eye symptoms. This indicates that a large percentage of people voluntarily purchase over-the-counter treatments to alleviate ocular discomfort and pinpoints a group that would benefit from a greater understanding of the disorder. With the aging United States “baby-boomer” generation, it is expected that the prevalence of dry eye will increase as will the number of patients with dry eye symptom.
In 1995 a group of researchers came up with the following definition of dry eye (the National Eye Institute/Industry report on dry eye):
“Dry eye is a disorder of the tear film due to tear deficiency or excessive tear evaporation which causes damage to the interpalpebral ocular surface and is associated with symptoms of ocular discomfort. “
What this means is that dry eye is defined as the presence of dry eye symptoms and microscopic damage to the front surface of the eye. Therefore, in the examination for dry eye the eye doctor asks questions about symptoms of dry eye, performs tests to determine how much tears the eyes produce, and looks closely at the front surface of the eye for damage. The following is a list of questions your doctor might ask:
- Do your eyes ever feel dry?
- Do you ever feel a gritty or sandy sensation in your eyes?
- Do your eyes ever have a burning sensation?
- Are your eyes ever red?
- Do you notice much crusting on your lashes?
- Do your eyes ever get stuck shut in the morning?
There are numerous treatments for dry eye. Usually, artificial tears (also called lubricant eye drops) are the first treatment tried for dry eye. Artificial tear drops come in two types of containers, individual unit dose containers and in bottles. The individual unit dose drops do not contain preservatives, while most of the bottled drops do have preservatives. Recently, several new artificial tears have come on to the market which have a hydrogen peroxide-based preservative that turns to water when it contacts the tear film of the eye and air. Therefore, bottled tears act like unpreserved tears, and may be more comfortable with frequent artificial tear usage. Examples are GenTeal (CIBA) and Refresh Tears (Allergan).
Some artificial tear drops are more viscous, or thick, and are recommended for night time use such as Allergan’s Celluvisc and Ocucoat. Often, a humidifier is used in the bedroom, especially if an individual does not adequately close their eyes, commonly referred to as “sleeping with your eyes open.” There are also lubricant ointments available.
If artificial tears are ineffective, or if using the drops is cumbersome, the next step is to consider punctal plugs. Punctal plugs are small pieces of soft silicone-plastic, which are inserted in the tear drainage canals. They act as a “dam” in preventing what tears the eye produces from draining or evaporating too quickly. The procedure is performed in the office with minimal discomfort. Punctal occlusion is not effective for all dry eye patients, and often artificial tears are used in conjunction with punctual occlusion.
New treatments are currently in development, including a drop called Restasis. This drop contains the drug cyclosporin, which reduces the inflammatory response thought to accompany dry eye. Other treatments, including topical androgen drops, are also in the development phases. Doctors and patients alike are anxiously awaiting new treatments for dry eye to better aid patient with dry eye symptoms.