Dry Eye Syndrome
Tears are a complex mixture of water, salts, oils, and proteins that help the surface of the eye remain smooth and uniform. Tears also wash away foreign material,such as allergens or bacteria, that may be harmful to the eye. Dry Eye Syndrome(DES) occurs when your natural tears are not able to adequately lubricate,coat, and protect the surface of your eyes. There can be many reasons for insufficient tears. In some cases, you may not produce enough tears or the tears that are being produced are of a poor quality so they evaporate more easily and do not cling to the surface of the eye properly. Age, hormonal imbalance, autoimmune disease, eyelid problems, medications, and environmental factors can directly cause or aggravate DES.
Dry Eye Symptoms and Signs
Common
symptoms and signs of DES include:
- Usually affects both eyes, but one eye may be affected more
- Eye discomfort, such as stinging, burning or a scratchy sensation
- Eye redness and/or eyelid redness
- Blurry vision or fluctuating vision
- Tearing
- Eye fatigue after reading for a period of time
- Light sensitivity, including glare or starbursts around lights
- Irritation from smoke or wind blowing into the eyes
- Waking up with stringy material in the corner of the eyes
- Uncomfortable contact lenses, especially towards end of day
- Eye infections, including from contact lens wear
- Scarring of the cornea (front clear window of the eye) in advanced cases
When dry eye symptoms affect vision or eye comfort, a detailed examination by your eye doctor can lead to treatment to improve or control these symptoms.
Composition of Tears
Tears consist of a mixture of water, oil, and mucus. Problems with any of these components may lead to DES.
- Oil layer: Fatty oils, or lipids, are secreted by small (meibomian) glands on the edge of the eyelid, near the eyelashes.
Location of Meibomian Glands at inner edge of eyelid. In some cases of Dry Eye Syndrome, the pores of the mibomian glands can get clogged preventing oils from flowing onto the surface of the eye. The oil forms a slick on the surface of the tears preventing evaporation of the underlying water layer. DES can develop when the meibomian glands
become clogged and stop secreting oils properly. Meibomian gland dysfunction (MGD) is more common with inflammation along the edge of the eyelids (blepharitis), rosacea, and other skin disorders. - Aqueous layer: The main component of tears is water mixed with salts, enzymes, and proteins. A complex mixture of water, salts or electrolytes, proteins, oils or lipids, mucin, and other molecules that interact to maintain a uniform tear film.This is produced by the lacrimal gland, which is
located underneath the outer aspect of the upper eyelid. If the lacrimal
gland becomes inflamed, its cells may no longer function normally and
produce less aqueous. - Mucous layer: Special (goblet) cells on the white
of the eye (conjunctiva) produce mucus, a thick, white material that coats
the superficial cells the eye and helps bind the aqueous layer of tears to
the surface cells.
Causes of Decreased Tear Production
- Age. Tear production tends to diminish with age.
- Female sex. DES is more common in women, especially after menopause, due to alterations in hormones. Testosterone
has been found to be important in the regulation of tears. - Medical conditions. DES is more common with medical conditions such as rheumatoid arthritis, lupus, Sjogren’s
syndrome, diabetes, and thyroid dysfunction. - Medications. Certain medications can decrease production of tears.
- Laser vision correction. Laser-assisted in-situ keratomileusis (LASIK) is associated with DES, which usually improves over several months after surgery.
Causes of Increased Tear Evaporation:
- Inadequate Oils in the Tears. Blockage of the oil tear (meibomian) glands on the edge of the eyelid can lead to easier tear evaporation. The Meibomian glands can become blocked and inflamed from chronic age-related skin changes, due to rosacea, and due to inadequate cleansing of the eyelash region.
problem that makes it difficult to blink, tears may not be spread across your eye adequately or your tears may evaporate too quickly, causing dry eyes. Eyelid problems can include an out-turning of the lids (ectropion), in-turning of the lids (entropion), or incomplete closure of the eyelids.
season can all be associated with more rapid evaporation of tears.
Medications Associated with Dry Eye Syndrome
- Blood Pressure medicines, such as diuretics (hydrochlorothiazide, Lasix)
- Antihistamines (Cetrizine) and decongestants
- Birth control pills
- Antidepressants
- Acne (Isotretinoin-based) medicines
Some basic questions you may want to discuss with your
doctor include:
- What is likely causing my dry eyes?
- What kinds of tests do I need?
- Are my dry eyes likely temporary or chronic?
- What are my treatment options?
- What are the potential side effects of each treatment?
- What are the alternatives to the primary approach that you're suggesting?
- Is there a generic alternative to the medicine you're prescribing me?
- Are there any brochures or other printed material that I can take with me? What websites do you recommend?
- When should I have a follow-up visit?
Diagnostic Tests for Dry Eye Syndrome
- Measuring the volume and quality of your tears.
-
Schirmer test. A filter strip with millimeter marking is placed on the lower eyelid. Tears flow onto this blotting
paper for 5 minutes, measuring the amount of tears asorbed during this interval. The normal range is from 10 – 20 mm in 5 minutes.
Dye Test. Various liquid dye eye drops can be applied to the surface of the eye. Areas that have a good coating of tears will dilute the dye. The dye will accumulate in drier regions because the tears are not adequate to
rinse away the dye.
Fluorescein (green) dry accumulates on the inferior portion of the eye as there are insufficient tears to wash away the dye.
-
Treatment of DES
For most people with mild dry eyes symptoms, treatment involves over-the-counter eye drops and other simple remedies, such as wearing sunglasses when outside or drinking more water. Keeping the eyelid area clean and opening pores of tear
glands in the eyelid are important for every dry eye patient. This can be done by cleansing the eyelash region (lid scrub) and applying heat and moisture (hot compress). If your dry eyes symptoms are persistent and more serious, there are a number of medical and surgical treatment options that can be of benefit.
Treating the underlying cause of dry eyes
Your doctor will work to determine what's causing your dry eyes. In some cases these situations can be reversed. For instance, if a medication is causing your dry eyes, your doctor may recommend a different medication that doesn't cause that side effect. If your symptoms are worse with computer work, then taking breaks during the work day may be helpful. If you have an eyelid condition, such as a condition that makes it difficult to close your eye completely when you blink, your doctor may refer you to an eye surgeon who specializes in plastic surgery of the eyelids. If your signs and symptoms suggest an autoimmune condition,
such as rheumatoid arthritis or Sjogren's syndrome, your doctor may refer you to a rheumatologist for evaluation.
Environmental Modification
If you experience dry eyes, pay attention to the situations that are most likely to cause your symptoms. Then find ways to avoid those situations in order to prevent your dry eyes symptoms. For instance:
- Avoid air blowing in your eyes. Don't direct hair dryers, car heaters, air conditioners or fans toward your eyes.
- Wear glasses on windy days and goggles while swimming. The wraparound style of glasses may help reduce the effects of the wind. Goggles protect your eyes from chemicals in pool water that can dry your eyes.
periodic eye breaks. Close your eyes for a few minutes. Or blink repeatedly for a few seconds to help spread your tears evenly over your eye.
view the screen. Position your computer screen below eye level. This may help slow the evaporation of your tears between eye blinks.
Lubricants
- Over-the-counter tear drops. There are many brands that are available at local pharmacies and grocery stores for the
treatment of DES. Your doctor can review which brands may be more effective for you. Generally, preservative-free eye drops, in twist-off vials, are better tolerated if topical lubricants are needed frequently. Depending on symptoms, drops may need to be used more frequently. Some people need to put drops in every hour, and some need eyedrops only once a day.
going to sleep. They moisturize the eyes overnight and may be helpful for someone waking up with eye discomfort.
lubricants.
patient’s own blood can be drawn to be used as a natural eye drop. A centrifuge, under sterile technique, is used to separate the red and white blood cells from the fluid in the blood. The fluid, or serum, is extracted and mixed with saline to create a 20% Serum tear solution. Serum contains proteins, oils, growth factors, anti-inflammatory agents, and other
components that can significantly improve the health of the ocular surface.
Eyelid Health
For people with eyelid inflammation (blepharitis) and other conditions that block the flow of oil to the eye, regular eyelid washing may help. Your doctor may recommend that you do this daily, even when you do not have dry eyes symptoms. stopping this daily routine may cause your dry eyes to return.
- Hot Washcloth. Wet a clean cloth with hot water. Hold the cloth over your eyes for five minutes. Re-wet the cloth with hot water when it cools. Gently rub the washcloth over your eyelids to loosen any debris. While this can be helpful and soothing, it is difficult to maintain an adequate amount of heat for a sufficient amount of time.
- Mild Soap Cleanser to Eyelid. Baby shampoo or other lid cleansers may be recommended by your doctor. Put the soap on your clean fingertips and gently massage your closed eyes near the base of your eyelashes. Rinse the soap completely
away. Pre-moistened lid cleansing pads are also commercially available.
Omega-3 Fatty Acid Supplements
Some preliminary research has suggested that omega-3 fatty acids could help relieve dry eyes symptoms. These fatty acids, found in fish and vegetable oils, are thought to reduce inflammation in the body, including in the eyes and eyelids. Omega-3 fatty acids are available in foods (salmon, tuna, flaxseed, walnuts) and in supplements.
Medications
- Antibiotics.
Antibiotics can decrease the amount of bacteria on the surface of the eye, can open up the pores of tear glands, and can help reduce eye inflammation. These are available in drop, ointment, and pill forms.
Agents. These can be used to control eye irritation and inflammation from chronic DES. Steroid and non-steroidal drops can be used to treat acute symptoms of redness and burning. Topical cyclosporine (Restasis) can be used on a long-term basis, including in patients with autoimmune conditions or after LASIK, to promote increased tear production by glands on the surface of the eye.
Office Treatment of DES
- Closure of the Tear Drain: Punctal Plugs. Normally tears drain through a canal in the inner corner of each eyelid into the sinuses and nose. This is why tears don’t normally spill down the cheek. Tiny silicone plugs or surgical cautery can
be used to block the tear drain, allowing the tears to remain in contact with the eyes longer. Plug insertion is an easy, reversible procedure that can be performed in the examination room and is usually covered by medical
insurance.