DR. DAVID HALLEGUA, ATTENDING PHYSICIAN WITH CEDARS-SINAI'S DIVISION OF RHEUMATOLOGY AND ASSISTANT CLINICAL PROFESSOR OF MEDICINE AT THE DAVID GEFFEN SCHOOL OF MEDICINE AT UCLA, ANSWERS QUESTIONS ABOUT DRY EYE SYNDROME.
WHAT IS DRY EYE?
Dry eye is defined as a condition in which there is reduced production of normal tears or excessive evaporation of tears resulting in damage to the exposed part of the eye and resulting eye symptoms. Though the initial symptoms are often thought to be no more than a nuisance, longstanding dry eye problems can lead to pits in the cornea, ulcers, thinning of the cornea and vision loss.
HOW OFTEN IS DRY EYE SEEN IN FIBROMYALGIA SYNDROME?
Dry eye syndrome (DES), also known as Keratoconjunctivis Sicca, and dry mouth syndromes have been found in about 15 percent of patients with fibromyalgia. Approximately 8.7 percent of women over the age of 50 have dry eye symptoms and about 64 percent of contact lens users suffer from dry eye symptoms at ant given time.
WHAT IS THOUGHT TO CAUSE DRY EYE SYMPTOMS IN FIBROMYALGIA?
Some studies suggest a role for commonly prescribed medications such as amitryptiline (Elavil) and cyclobenzeprine (Flexeril) in causing DES in fibromyalgia syndrome (FMS). Others suggest more common causes.
* Seborrheic dermatitis and acne rosacea, which are disorders of the glands present in the eyelids and face, can cause chronic inflammation of the glands in the eyelid (called meibomian glands), causing abnormal tear function with lack of protective natural oils resulting in DES.
* An autoimmune cause for dry eye in FMS similar to Sjogren's syndrome has been investigated by several investigators. They found a slightly higher number of FMS patients who have DES with a positive antinuclear antibody but no clear evidence of definite Sjogren's syndrome.
* Decreasing adrenal hormone levels associated with aging has been associated with DES. Low levels of adrenal hormone levels have also been demonstrated in FMS.
* Dysfunction of the autonomic nervous system with poor stimulation of the lacrimal gland to produce tears is thought to play a role in half or more of the patients with DES but has not been proven.
* Subjective poor health and fatigue, not associated with FMS or depression, is associated with dry eye syndrome suggesting that dysfunction of the brain and nervous system may cause dry eye symptoms.
* Excessive sensitivity of nerve cells sensing pain from the eye may enhance symptoms of dry eye in FMS.
WHAT ARE THE COMMON SYMPTOMS OF DRY EYE?
Symptoms of dry eye include itching, redness, eye fatigue, dryness, irritation, crusting of lids, scratchiness, excessive tearing, discharge, blurry vision, pain, light sensitivity, blinking abnormalities, foreign body sensation and burning. Tearing occurs in dry eye because irritation provoked tearing may not be affected compared to basal levels of tear production.
Many questionnaires have been developed to study dry - eye symptoms. The most commonly used questionnaire for research purposes is the Ocular Surface Disease Index (OSDI), which consists of 12 questions with a score ranging from zero to four for each question. The OSDI score is calculated from the total score and number of questions answered is used to assess the severity of DES present.
WHAT PHYSICAL EXAM CHARACTERISTICS AND TESTS ARE DONE TO CONFIRM DRY EYE? Examination of the eye should 'include the search for eyelid inflammation and dilated blood vessels on the conjunctiva due to rosacea of the eye. Other signs such as redness, crusting and tearing are nonspecific. Among the many tests available to confirm dry eye syndrome, the one that is most commonly uses is the Schirmer's I test In this test, the eye is numbed with a, drop of local anesthetic and a thin paper strip is tucked into the lower eyelid to measure the wetting due to tears in 5 minutes. Dry eye is confirmed if there is less than 5 mm of wetting of the strip. The test is limited in not being very sensitive, especially in situations of evaporative tear loss when the test may be falsely normal (>15mm in 5 minutes). In the research setting, an additional test must be positive for dry eye in order to definitively diagnose it.
Two other tests commonly used are the Tear Break Up Test (TBUT) and Corneal Staining tests with Fluorescein or Rose Bengal stains. In TBUT, the time taken for a tear film stained with fluorescein to break up is clocked (normal- > 10 seconds). In the staining tests, the cornea is divided into segments and the degree of damage to the outer lining cell layer is estimated and totaled to give a score, which is diagnostic. Patients with evaporative tear deficiency will have abnormal TBUT and corneal staining tests.
HOW CAN DRY EYE BE TREATED IN FI BROMYALGIA?
Common sense approaches in treating dry eye symptoms in FMS include avoiding low humidity situations as much as possible, such as avoiding using blow dryers and reducing the use of forced dry air heat. Exposure to high winds during and boat motorcycle rides without proper eyewear and long airplane flights also exacerbate dry eye symptoms. Computers should be kept at eye level or lower to avoid excessive exposure of the eye surface for long periods of time. Artificial tears should be used more frequently in these situations. Hot compresses to the eye for five minutes a few times each day can increase oil secretions from the meibomian glands.
The cornerstone of treatment for dry eye syndrome from any condition is to enhance the wetness of the exposed eye surface with a physiologically similar tear substitute and retain the artificial tears in the eye as long as possible.
INCREASING MOISTNESS 0F THE CORNEA AND CONJUNCTIVA
Artificial tears are made with and without preservatives and may include oil supplements that try to mimic the lipid, water and mucus triple layer of natural tears. The basic component of artificial tears is a hydrogel, which retains moisture and adheres to the corneal surface. Tears produced in DES have an increased osmalality or an increase in dissolved elements and substances. This damages the cell lining of the cornea and therefore a hypotonic artificial tear product will help to correct this imbalance and promote healing. Oil or lipid-containing artificial tears try to restore the trilayer emulsion coating of the eye. Increasing the viscosity can help to increase the adherence to the eye at the expense of possibly causing blurring of vision. Preservatives such as benzalkonium chloride and chlorbutanol can cause a lot of irritation to the severely dry eye. Preservative free artificial tears or newer preservatives, such as polyquaternium-1 (Polyquad) and sodium perboate (Genqua), can avoid this issue.
Thus the best approach is to combine artificial tears with different characteristics to obtain different benefits. For example, combining an agent with increased viscosity (Systane) with a preservative free hypotonic artificial tear (Thera) every four to six hours followed by a preservative¬free (Refresh PM7) ointment at bedtime would give the benefits of all the products while minimizing side-effects. Oil¬containing drops such as Soothe may be used if meibomian gland deficiency is suspected.
The amount of tears produced may be increased by using a lacrimal gland-stimulating agent, such as pilocarpine (Salgen) or cevimiline (Evoxac) tablets. Pilocarpine in doses of 10 to 30 mg four times a day and cevimiline in doses of 30 to 60 mg three times a day have shown to reduce dry eye symptoms and promote healing of the eye surface in controlled clinical trials. Side effects include sweating, urinary urgency and diarrhea.
The role of inflammation in causing dry eye symptoms has led to the use of topical cyclosporin 0.05 percent in an oil emulsion vehicle twice a day with improvement in healing or corneal defects after three months of treatment when compared to the vehicle alone. Side effects include a mild stinging sensation that disappears in one month. No infections were seen and systemic absorption is minimal.
Other approaches in decreasing inflammation includes increasing polyunsaturated omega-3 and omega-6 fatty acids in the diet with either fish oil supplements or flax seed oil supplements in order to supply at least 15 mg of omega-3 and 28.5 mg of omega-6 fatty acid which was shown to be beneficial in one clinical trial.
Dehydroepiandrosterone (DHEA) deficiency has been thought to contribute to the cause of dry eye associated with meibomian gland dysfunction and the dry eye syndrome of aging and Sjogren's syndrome. A randomized trial of 200 mg per day of DHEA supplementation for six months in a small group of Sjogren's patients was not successful in relieving dry eve symptoms or signs when compared with placebo. DHEA deficiencv has been demonstrated in FMS as well.
Acupuncture has been shown to be helpful in relieving eye symptoms in non-autoimmune dry eye syndromes.
RETAINING TEARS IN THE CONJUNCTIVAL SAC
The upper and lower lacrimal ducts allow the drainage and loss of 60 percent of the basal tear production and most of the artificial tears instilled in the eye via the nasolacrimal duct. Plugging the duct with temporary collagen plugs followed by permanent silicone or acrylic polymer plugs may help to retain moisture. Side effects include irritation of the conjunctiva with plugs that are completely inserted and extrusion of about of half the plugs inserted at six months. Newer acrylic polymer plugs help to avoid some of these problems.
About 25 percent of basal tears and artificial tears are lost from evaporation from the conjunctival and corneal surface. Various goggles and chambers have been developed to be worn in dry climates and when participating in various sports such as snowboarding, boating and motorcycle riding.
For a detailed list of dry-eye treatment products, visit the NFA's website, www.fmaware.org.
Dry eye symptoms are common in FMS and should be managed with patient education to limit activities that increase dryness of the eye and with the use of judicious dietary and prescription aids. Serious complications such as corneal ulceration and scarring can be avoided with proper diagnosis and treatment. Research in developing agents that stimulate mucous production directly from the lining of the eye rather than lacrimal gland and androgen eye drops to retard inflammation in the eye is active and promising
Source: Fibromyalgia Aware, October 2005-January 2006 (Brought with permission from Fibromyalgia Aware.)