Dry eye syndrome is one of the most common problems treated by eye physicians. Over ten million Americans suffer from dry eyes. It is usually caused by a problem with the quality of the tear film that lubricates the eyes.
Tears are comprised of three layers. The mucus layer coats the cornea, the eye’s clear outer window, forming a foundation so the tear film can adhere to the eye. The middle aqueous layer provides moisture and supplies oxygen and other important nutrients to the cornea. This layer is made of 98 percent water along with small amounts of salt, proteins and other compounds. The outer lipid layer is an oily film that seals the tear film on the eye and helps to prevent evaporation.
Tears are formed in several glands around the eye. The water layer is produced in the lacrimal gland located under the upper eyelid. Several smaller glands in the lids make the oil and mucus layers. With each blink, the eyelids spread the tears over the eye. Excess tears flow into two tiny drainage ducts in the corner of the eye by the nose. These ducts lead to tiny canals that connect to the nasal passage. The connection between the tear ducts and the nasal passage is the reason that crying causes a runny nose.
In addition to lubricating the eye, tears are also produced as a reflex response to outside stimulus such as an injury or emotion. However, reflex tears do little to soothe a dry eye, which is why someone with watery eyes may still complain of irritation.
Dry eye syndrome has many causes. One of the most common reasons for dryness is simply the normal aging process. As we grow older, our bodies produce less oil – 60% less at age 65 then at age 18. This is more pronounced in women, who tend to have drier skin then men. The oil deficiency also affects the tear film. Without as much oil to seal the watery layer, the tear film evaporates much faster, leaving dry areas on the cornea.
Another significant factor contributing to Dry Eye Syndrome is a lid dysfunction called meibomitis (meibomian gland dysfunction). Meibomeitis can often be associated with facial skin infections, acne, acne rosacea or other facial skin disorders. Other associated factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people also find their eyes become irritated when reading or working on a computer. This may be from blinking inactivity from subconscious attentiveness to such visual tasks. Stopping periodically to rest and blink keeps the eyes more comfortable.
Contact lens wearers may also suffer from dryness because the contacts absorb the tear film, causing proteins to form on the surface of the lens. Certain medications, thyroid conditions, vitamin A deficiency, and diseases such as PARKINSON’s and SJOGRENS’s syndrome can also cause dryness. Women frequently experience problems with dry eyes as they enter menopause because of hormonal changes.
Possible symptoms of Dry Eye Syndrome:
• Blurred vision that improves with blinking
• Excessive tearing
• Increased discomfort after periods of reading, watching TV, or working on a computer
Detection and Diagnosis
There are several methods to test for dry eyes. The doctor will first determine the underlying cause by measuring the production evaporation rate and quality of the tear film. Special drops that highlight problems that would be otherwise invisible are particularly helpful to diagnose the presence and extent of the dryness. Depending on the symptoms and presentation Dry Eye Syndrome can be classified into mild, moderate and severe. Some of the guidelines that can be used to manage various stages of Dry Eye Syndrome are:
When it comes to treating dry eyes, everyone’s needs are a little different. There are three strategies for treatment.
1. Tear replacement. Many find relief simply from using over the counter ARTIFICIAL TEARS and or lubricating eye creams on a regular basis. Some of these products are watery and alleviate the symptoms temporarily; others are thicker and adhere to the eye longer. Preservative-free tears are recommended because they are the most soothing and have fewer additives that could potentially irritate. Avoid products that whiten the eyes – they don’t have adequate lubricating qualities and often make the problem worse.
2. Tear drainage prevention. Closing the opening of the tear drain in the eyelid with special inserts called PUNCTAL PLUGS is another option. This works like closing a sink drain with a stopper. These special plugs trap the tears on the eye, keeping it moist. This may be done on a temporary basis with a dissolvable collagen plug, or permanently with a silicone plug.
3. Resulting irritation prevention. Certain cases respond to prescription strength medications such as eyedrops. Restasis is a comparatively expensive alternative and it does not work in all patients. Providing there is not an allergic or other reaction, the patient has to be on the drops for about one month prior experiencing a benefit.
If meibomeitis is present topical and sometimes systemic antibiotics may be indicated as adjunctive treatments for the tearing problems.
There are also simple lifestyle changes that can significantly improve irritation from dry eyes. For example, drinking eight to ten glasses of water each day keeps the body hydrated and flushes impurities. Make a conscious effort to blink frequently – especially when reading or watching television. Avoid rubbing the eyes. This only worsens the irritation.