CHRONIC DRY EYES

Chronic dry eyes is one of the most common conditions that ophthalmologists encounter. It is characterized by symptoms of discomfort and visual disturbance.

How common is dry eye syndrome?

Keratoconjunctivitis sicca is a common condition. Studies report that 17-30% of people experience chronic dry eyes at some point during their life.

What causes dry eye syndrome?

Keratoconjunctivitis sicca can have many different causes, including environmental factors, illnesses, side effects of medicines, hormonal changes, and aging. In many instances, there is no single identifiable cause for dry eye disease, but rather a group of causes.

Who is affected by dry eye syndrome?

Keratoconjunctivitis sicca often occurs in people who are otherwise healthy. It is more common with older age, because people produce fewer tears with age. Chronic dry eyes is more common among women than men. The condition usually is not serious.

THE IMPORTANCE OF TEARS

Our eyes constantly are covered by a thin layer of liquid, known as the tear film. Tears serve the following important functions:

• Lubrication of the eye.
• Maintain the eye clean and free of dust.
• Protection against infection.
• Aid sight by helping to stabilize vision.

Problems in any of these components can cause the entire lacrimal apparatus to collapse. This affects the quantity (not enough tears made) and/or quality (tears evaporate before they can be replaced) of tears produced. These both can result in dry eye disease.

Complicating matters, the immune system attempts to compensate for the lacrimal apparatus collapse by sending infection-fighting cells to the eye. These cells cause the eye inflammation that is associated with more serious cases of dry eye syndrome.

RISK FACTORS FOR DRY EYE SYNDROME

A number of things can affect the normal function of the ocular surface. Common risk factors for chronic dry eyes include:

• Medications. Common systemic medications, including antihistamines, decongestants, diuretics, anti-depressants, oral contraceptives, beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, carbonic anhydrase inhibitors, and isotretinoin can cause or exacerbate dry eye symptoms.
• Climate. Low humidity can worsen symptoms in patients with existing symptoms and may exacerbate dry eye symptoms in asymptomatic individuals with a marginal tear film. Upwardly-directed forced air vents also can have negative effects on a patient’s tear film and cause dry eye symptoms to worsen.
• Extensive Visual Tasking. Time spent at video display terminals (computer monitors, video games) stresses the integrity of the tear film and can lead to dry eye disease. A recent study found that patients with chronic dry eyes working in front of a computer monitor had an average spontaneous eye blink rate of less than half of the rate of patients with chronic dry eyes engaged in conversation (6.6 blinks/min vs. 16.8 blinks/min).
• Aging. Aging increases a patient’s risk for developing keratoconjunctivitis sicca. In women, menopausal and postmenopausal hormonal changes can affect tear film integrity. Women taking hormone replacement therapy also have an increased risk of keratoconjunctivitis sicca.
• Nutrition. Research suggests that nutrition plays a more significant role in ocular surface health than previously believed. A study of more than 30,000 females found that those consuming significantly more omega-6 than omega-3 fatty acid (ratio greater than 15:1) had an increased risk of chronic dry eyes compared to those that consumed a more balanced fatty acid intake (less than 4:1).
• Contact lenses. Contact lens wear is another significant risk factor for dry eye disease. Several studies have shown that over 50% of current contact lens wearers complain of dry eye symptoms.

SYMPTOMS OF DRY EYE SYNDROME

Symptoms of dry eye syndrome can be mild or severe. They include:

• Dryness, grittiness, or soreness in both eyes that gets worse throughout the day.
• Eye redness.
• Watery eyes, especially when exposed to wind.
• Sticky eyelids upon waking in the morning.

If left untreated, chronic dry eyes can cause complications, such as scarring of the cornea (the transparent layer at the front of the eye) and conjunctivitis (inflammation, or infection, of your eye). These complications can produce more severe dry eye symptoms. Among these are:

• Extreme sensitivity to light (photophobia)
• Extreme eye redness.
• Eye pain.
• Blurry vision.

Visit your ophthalmologist as soon as possible if the above dry eye symptoms occur.

DIAGNOSIS OF DRY EYE SYNDROME

Your ophthalmologist should be able to diagnose keratoconjunctivitis sicca by your symptoms and your medical history. She or he will want to know about any medicines that you are taking, and your personal circumstances, in case a possible cause of your chronic dry eyes can be identified. A thorough examination will check for other conditions and complications.

An ophthalmologist can assess the quality and quantity of your tears using the following tests.

• Flourescein Staining is used to assess the quality of tears in patients with suspected dry eye disease. Flourescein dye readily dissolves into the tear film and can be used to assess its integrity by measuring tear film break-up time (TFBUT). After applying flourescein onto the ocular surface, the patient blinks their eyes to spread it, and then holds them open. The time from the end of the blink to the appearance of the first dark region (evaporation area) in the flourescein pattern is the TFBUT. Healthy patients generally demonstrate a TFBUT greater than 10 seconds.
• Schirmer Testing evaluates quantity of tears in patients with suspected dry eye disease by placing small strips of blotting paper under the eyelid. After five minutes, the strips are removed and studied in order to see how wet the paper is.
• Lissamine Green and Rose Bengal Testing is used to detect dead and devitalized cells on the cornea and conjunctiva in patients with suspected dry eye disease.
• Phenol Red Thread Testing is an alternative to Schirmer testing to assess the quantity of tears produced in patients with suspected dry eye disease.

PREVENTION OF CHRONIC DRY EYES

There are several things that you can do to help prevent, or reduce, dry eye symptoms.

• Maintain clean eyes. This will help prevent chronic dry eyes and its associated condition blepharitis. Gently clean your eyelids using a cotton ball and warm water. A cotton swab also can be used to remove any crustiness from your upper and lower eyelids. Gently massage your eyes by rolling your forefinger over them in a circular motion. This will help to push out any of the mucus-like fluid from the tiny meibomian glands.
• Use wraparound glasses to protect your eyes from wind and/or hot air.
• Take regular rest periods from using a computer or playing video games. Take a 5-minute break for every 30 minutes that you spend on the computer. If this is not feasible at work, rest your eyes by closing them for 30-60 seconds instead. The key is to break up the pattern of low blink rate that accompanies computer work or video-game playing. Additionally, position your computer workstation correctly to minimize eye strain. Your monitor should be at, or just below, eye level.
• Stop smoking and avoid smoke to reduce irritation to your eyes.
• Use a humidifier. This will help to moisten the surrounding air. Alternatively, open windows for a few minutes on cold days, and longer in the spring and summer. This will also help to keep the air moist and prevent the build-up of mold.
• Eat a balanced diet that is high in omega-3 fatty acids. Good sources of omega-3 fats are mackerel, salmon, sardines, tuna, herring, olives, olive oil, amaranth, quinoa, kidney beans, navy beans, tofu, walnuts, brazil nuts, soy nuts, pumpkin seeds, winter and summer squash, raspberries, strawberries, broccoli, cauliflower, green beans, romaine lettuce, and collard greens.

TREATMENT OF DRY EYE SYNDROME

• Artificial tears. These have become a mainstay of therapy for dry eye symptoms. The success or failure of artificial tear therapy for keratoconjunctivitis sicca depends on several factors, including patient adherence to the prescribed medication regimen and the type of artificial tear used.
• Environmental modifications. There are several simple changes that can be made to reduce the appearance and severity of chronic dry eyes. Among these are avoiding exposure to wind, redirecting ventilation that is pointed upward or avoiding it, and avoiding extensive computer or video-game use. See below for other things that you can do to reduce the severity of dry eye symptoms.
• Improved nutrition. Obtaining omega-3 fats from food and/or the use of nutritional supplements is important for treating dry eye disease. Maintaining good hydration also is essential. Caffeinated and alcoholic drinks can lead to a dehydrated state if they are not balanced by water intake.
• Anti-inflammatory medications. Inflammation is directly associated with keratoconjunctivitis sicca. Lotemax (loteprednol etabonate 0.5%) and Restasis (cyclosporine 0.05%) are two common medications used in the treatment of keratoconjunctivitis sicca
• Special eyewear. Some cases of dry eye syndrome can be treated using moisture chamber eyewear. These wrap around your eyes like goggles, helping to retain moisture and protect the eyes from irritants. At one point, people were embarrassed to wear moisture chamber eyeglasses because they looked strange. However, current designs look just like sports sunglasses, making them a more popular treatment option.
• Treatment of eyelids. The eyelids play an essential role in overall tear film health. The meibomian glands are sebaceous glands located at the eyelid margin just posterior to the eye lashes. Anything that affects meibomian gland function will reduce lipid flow and compromise tear film health.
• Surgery. For severe cases of dry eye disease or for those that do not respond to other treatment options, surgical intervention may be required.

REFERENCE:

Asbell P and Lemp M. Dry Eye Disease: The Clinician's Guide to Diagnosis and Treatment. New York: Thieme, 2006.

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