| What
is Dry Eye?
One of the more common causes of eye irritation is known as Dry Eye Syndrome. Dry eyes are estimated to affect 12 million Americans.
Symptoms of dry eye are typically a sensation of regular eye irritation, burning, tearing, and sometimes blurry vision. The tear film which covers the surface of the eye is a complex 3 layered structure which has many functions. It is made mostly of water, but also has an inner layer of mucus, which holds the tear film to the eye surface and an outer layer of lipids (fats) which
serves to slow evaporation of tears. This tear film lubricates the eye, smoothes irregularities for better
quality vision, washes germs and other irritating substances from the eye surface and carries
important oxygen to the surface of the eye. Dry eye is a label for various disorders of the tear film which may be classified into two categories: (1) decreased tear production or (2) excessive tear evaporation. Dry eye may also develop as a result of disease in the oil-producing glands within the eyelid. Regardless of the mechanism, water is lost from the tear film, making it more "concentrated". This lack of water draws water from the surrounding eye tissues, leading to further deterioration of the health of the eye surface. Eventually, dry, rough spots appear on the eye surface, which typically the quality of vision, and increases risk for eye infection and problems with contact lens use. In severe cases,
permanent corneal scarring may develop.
Who is at Risk to Suffer from Dry Eyes?
Dry eye becomes more common with increasing age and as body hormone changes develop. Most commonly affected are post-menopausal women. Certain autoimmune conditions, such as Rheumatoid arthritis and Sjogren's syndrome, occur together with dry eyes. Medications taken by mouth are another common cause of dry eyes. In particular, several categories of drugs are more likely to cause dry eye, including:
• Blood pressure medications
• Antidepressants
• Certain medications which regulate heart rhythm irregularities
• Decongestants
• Antihistamines
• Medications for Parkinson's Disease
More rarely, there can be a genetic or hereditary cause of dry eyes. For many who have dry eyes, environmental conditions may be an important factor worsening symptoms (construction jobs, janitorial work). Most likely to cause worsening of dry eye are low humidity environments, wind, central heat or air conditioning and airplane travel. One very common reason for dry eyes that is often overlooked, is sleep pattern problems such as snoring and sleep apnea. These can create a lack of complete eyelid closure for prolonged periods of time during sleep, which make the corneal surface dry and speckled like sand paper in the morning for lack of moisture during those sleep moments of incomplete lid closure.
How is Dry Eye Diagnosed?
Dry eye disorders can pose a challenging problem in diagnosis for physicians. Many different factors can contribute to dry eyes, and determining the cause may affect selection of the best treatment. Most important is listening carefully to a patient's history. Patients with dry eye are typically symptomatic for at least six months, and complain of a collection of symptoms which worsen as the day goes on:
• sandy, gritty sensation
• eye redness
• burning or stinging
• dryness
• blurred vision
• foreign-body sensation
• contact lens intolerance
Examination of the eyes is important to identify any eyelid abnormalities which may be present and contribute to symptoms of dry eye. Failing to correct eyelid problems often results in failure to relieve symptoms. A careful eye examination allows the physician to test the quality, quantity and stability of the tears and to look for irritation of the eye surface. Special dyes (colored eyedrops) may reveal characteristic findings of dry eyes. Although not mandatory, but helpful, is the Schirmer’s tear test, which can be done by the doctor in the office, and serves to actually measure the tear film in a quantitative way.
How is Dry Eye Treated?
The initial approach to treating
dry eye syndrome is directed at treatment of the underlying
cause. To start with the doctor typically starts with a
special dosage of topical tear substitutes (drops, gels
or ointments). Many varieties are available, including thin,
watery tear substitutes and thicker, more viscous eyedrops.
Several brands include electrolytes (salts) which may help
heal the damaging effects of dry or "concentrated"
tears on the surface of the eye. Ointments may be very soothing
but should only be used at bedtime (to minimize the blurring
produced). There is now available a very strong dry eye
prescription eye drop medication used only in the most severe
cases. When symptoms persist despite the use of tear substitutes,
temporary or permanent closure of the tear ducts may be
considered (punctual plugs or thermal punctual occlusion).
This very valuable approach is similar to placing a plug
in the drain in order to help a slow-running faucet fill
a kitchen sink. Each eyelid has two "drains" or
tear ducts near the bridge of the nose (one on the upper
eyelid and one on the lower eyelid; both being located near
the nasal side of the eyelid). Temporary plugs are available
to test whether this treatment will offer relief of symptoms
and are used before "permanent" (though removable)
silicone plugs are inserted. This is done as a minor office
procedure and can produce dramatic relief of dry eye symptoms.
Strategies to increase the local humidity near the eyes
may be very helpful for the more severe cases of dry eye.
Drinking plenty of water each day, if not already doing
so, enables definite help in this process. Plastic side
shields attached to eyeglasses help prevent rapid evaporation
of tears and may be very useful. In very severe cases, it
may be necessary to suture the eyelids partially together
at the corners to reduce the area exposed, also slowing
loss of tears to evaporation. There are now available specific
eye medications that for many individuals satisfy their
dry eye symptoms immensely. Alternatives to treatment of
sleep apnea are now available that don’t tend to dry
out the corneal surface as much as the head breathing apparatus
has done in many eyes.
What is Being Learned from Current Research on Dry Eye?
Current research has revealed much new information about what causes dry eye to develop. The role of hormonal factors are becoming betterunderstood, and in time can change how we treat dry eye. Within several years, hormone-containing tear substitutes may become available. Much work has been done on the use of medications which reduce inflammation on the eye surface. Eyedrops containing cyclosporine have been studied and appear to be the first medication which actually treats the cause of dry eye, rather than simply treating the symptoms. Our office has been very involved in this research for the past several years particularly in regards to flaxseed oil as another treatment option for dry eye syndrome.
Dry Eye Video
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