Cause and symptoms of dry eye syndrome

What is dry eye syndrome?

Dry eye syndrome is one of the most common problems treated by eye physicians. It is usually caused by a problem with the quality of the tear film that lubricates the eyes. 

What is the components of tears?

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.  

The causes of dry eye syndrome:

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.

Many other 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.  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 Sjogren’s can also cause dryness.  Women frequently experience problems with dry eyes as they enter menopause because of hormonal changes.  

The symptoms of dry eye: 

• Tearing
• Burning
• Irritation
• Itching
• Blurred vision that improves with blinking
• Redness
• Increased discomfort after a long period of reading, watching TV, or computer

Diagnosis of dry eye:

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. 

Treatment: 

Relief can simply result from using artificial tears on a regularly.  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. 

Closing the opening of the tear drain in the eyelid with punctal plugs is another option. 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. 

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.