Dry eye syndrome is a multifactorial ocular disease that is poorly understood. Discomfort, visual disturbance, and tear film instability are common complaints. Left untreated, dry eye syndrome is usually progressive in nature.
Studies have shown that nearly 5 million Americans age 50 or older are significantly affected by dry eye disease. Women are affected twice as often as men, and the disease appears to be more common in those 45 years of age and older. The Beaver Dam Eye Study showed that age was the biggest contributory factor to dry eye syndrome.
Those with diabetes or immunocompromised conditions such as Sjogren’s syndrome, rheumatoid arthritis, and multiple sclerosis also have a higher incidence of dry eye syndrome. Patients with arthritis, smokers, contact lens wearers, and those who have undergone hormone replacement therapy (in particular, estrogen) are more likely to suffer with this condition.
Reduced levels of sex hormones, especially androgen, are considered to be a major component in the pathophysiology of dry eye syndrome. Decreasing hormone levels with age appear to be the “breaking point” at which women, in particular, begin to suffer from the effects of dry eyes.
Various environmental factors affect dry eye syndrome. Visual tasks such as computer use, reading, or watching TV will exacerbate symptoms. One’s blink rate decreases during activities such as driving or reading. Patients also need to be aware of the location of air conditioner vents, ceiling fan placement, exhaust fumes, and smoke in their environment, as all of these can worsen the effects of dry eye syndrome. Low humidity will also intensify the symptoms of dry eye.
Dry eye syndrome is the most frequently reported complaint after LASIK.
Systemic medications including antihistamines, blood pressure medications, thyroid medications, antianxiety medications, antidepressants, diuretics, and hormone replacement therapy aggravate dry eyes. Drinking alcohol or living in a dry, arid locale are other risk factors.
The tear film that coats the eye is composed of three layers: a lipid layer, an aquaeous (water) layer, and a mucous layer. If any of these becomes unstable, the result will be a dry eye.
Symptoms of dry eye syndrome include sensitivity to light, foreign-body sensation, red eye, burning, excess tearing, or sharp, stabbing pain. Amazingly, some patients present with no symptoms, but have obvious superficial corneal damage on examination. This is why you cannot treat dry eye syndrome effectively based on how you feel. By the time you begin experiencing any of the above symptoms, you have usually been unacceptably dry for quite some time.
Tearing, a common complaint in patients with dry eyes, is also a source of confusion in this syndrome. It simply represents a protective reflex in the ocular system. Your eyes will reflexively “water” on a dry windy day and this is the same reflex that kicks in when your eyes naturally become too dry.
There are many uncontrollable dietary, environmental, and genetic factors that make it more difficult to determine the impact of diet specifically on dry eye syndrome. It is important to remember a balanced diet may preserve a patient’s visual acuity as well as improve their ocular comfort.
Recent research indicates that an increased intake of poly-unsaturated fatty acids can slow or prevent the progression of dry eye, among other ocular conditions. There are two types of PUFAs: omega-3 and omega-6. Both are responsible for regulating metabolism, stimulating skin and hair growth, and maintaining healthy bones and vision. Fried and processed foods are high in omega-6, while foods such as fatty fish are high in omega-3. A healthy ratio is recommended to be two to five omega-6’s to every one omega-3. In our culture, it’s often as high as 10:1 to 25:1.
Therapeutic approaches for mild to moderate symptoms include artificial tears, use of hypoallergenic products, patient counseling, and increased water intake.
Severe dry eye syndrome may require oral tetracycline and/or punctal plugs — tiny devices placed within the nasal opening of the eyelid to prevent what little lubrication the eye is producing from draining out of the eye as quickly. Patients with severe symptoms and severe corneal damage may require oral immunosuppressive medications, surgery, punctual cautery, moisture goggles, or oral anti-inflammatory medications.
Patients usually need to be followed every few weeks, depending on the severity of the symptoms, until an effective management plan can take effect. Those with an underlying chronic systemic disease may need to be monitored more closely. These patients seem to struggle more with dry eyes than those that aren’t immunosuppressed.
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Dr. Valerie Moulds is affiliated with Eye Specialists of Mid-Florida, 5032 U.S. 27 N., Sebring.