Exposure to drying winds, high altitudes, high room temperature, indoor pollution, or poor air quality (including smog and smoke) can increase the rate of tear evaporation. Activities that are reduce the amount of times you blink, such as looking at a computer monitor, can also result in symptoms of Dry Eye.1,2
As you age, the likelihood that you will experience Dry Eye increases.1 One reason for this is that 60% less oil is produced by the human body at age 65 than at age 18. Decreased oil production affects women more than men due to hormonal changes after menopause. Because oil is needed to seal the tear film onto the eye surface, insufficient oil production will allow the tears to evaporate too quickly, leaving dry spots on the eye.3
Women tend to report Dry Eye symptoms more frequently than men. This could possibly be due to hormone fluctuations during the menstrual cycle or after menopause as well as the use of oral contraceptives or hormone replacement therapy.1
Pregnancy and Dry Eye: pregnant women may experience pregnancy-induced Dry Eye. It's quite common to have dry eyes while pregnant due to huge hormone level alterations.4
Symptoms of Dry Eye commonly occur soon after some surgeries such as LASIK, as well as cataract surgery. Dry Eye can be caused by the medications that your doctor prescribed for you after the surgery because of changes to the eye surface that were caused by the surgery.1,5
Laser eye surgery (laser-assisted in situ keratomileusis): Laser eye surgery is commonly performed to correct vision. Symptoms of Dry Eye occur in nearly all patients after laser eye surgery and tend to be worse in the period immediately following surgery. Usually tearing will return to normal within nine months with the help of appropriate medications and treatment prescribed by your doctor. Dry Eye can be caused by the medications that your doctor prescribed for you after the surgery or because of changes to the eye surface that were caused by the surgery. It is also possible to already have Dry Eye that is made worse by the surgery.1,5
Cataract surgery: A cataract is a clouding of the lens in the eye that affects vision. It needs to be removed when vision loss interferes with everyday activities. There are two types of cataract surgery: phacoemulsification and extracapsular. In phacoemulsification, a small incision is made on the side of the cornea into which a tiny probe is inserted. The probe emits ultrasound waves that break up the lens. The lens is then removed by suction and replaced by an artificial lens. Extracapsular surgery involves a longer incision to remove the cloudy core of the lens in one piece. Cataract surgery is the surgical procedure where the cloudy lens is removed and replaced with an artificial lens. Dry Eye may interfere with wound healing in patients who undergo cataract surgery. When you get a cut on your skin there is inflammation and eye surgery is no different.1,5
Chronic blepharitis and meibomian gland dysfunction (also known as MGD, or meibomian gland disease) are associated with symptoms and signs of Dry Eye.1,2 For people with chronic blepharitis and meibomian gland dysfunction, which may be associated with Dry Eye, eyelid hygiene is very important. Cleaning the eyelid will remove irritating debris, increase eyelid blood flow, and open up blocked meibomian glands.2
Blepharitis: Blepharitis is characterized by inflamed eyelids. It can either affect the outside of the eyelids or the inner eyelid. With this condition, the oil glands (or meibomian glands) in the eyelid become damaged as a result of inflammation. When this happens, oil that is necessary to prevent water loss is decreased. This will cause tears to evaporate too quickly. Blepharitis can lead to meibomian gland dysfunction.1,2
Meibomian gland dysfunction (MGD): The meibomian glands are located in the upper and lower eyelids and produce oil that is released into the tear film. Oil is necessary to prevent the water in tears from evaporating. Meibomian gland dysfunction occurs when the oil becomes thicker than normal and plugs the glands, preventing them from delivering oil to the surface of the tear film. This condition is the most common cause of evaporative Dry Eye.1,7
Rheumatoid arthritis, diabetes, autoimmune disorders such as Sjögren’s syndrome, lupus, and atopy are all associated with Dry Eye. These diseases may cause inflammation in the eye that causes dysfunction or disappearance of the cells that are responsible for producing enough tears.1
Sjögren’s syndrome: This is an autoimmune disorder that attacks the tear and saliva glands, causing dryness of the eyes and mouth. It has been associated with severe forms of Dry Eye.1
Many contact lens wearers experience eye dryness. In fact, 50% to 75% of contact lens wearers experience eye irritation associated with Dry Eye. This is often the reason many people stop wearing contact lenses. Contact lenses that have a high water content may be a contributing factor. The water will evaporate from the lens, causing it to dry out.1,8
Another explanation could be that in contact lens wearers with Dry Eye, the layer of tears found on the contact lens thins much faster than for contact lens wearers without Dry Eye. This could be related to the fact that the surface of certain contact lenses do not retain moisture well, and could be the reason why tears evaporate too quickly during contact lens wear.1
Wearing contact lenses for too long may also cause Dry Eye symptoms. Proper treatment of Dry Eye may allow contact lens users to wear them comfortably again.9
Medications may affect the eye’s ability to create tears. Some of these medications are.2
- Birth Control Pills
Pregnancy and menopause may be risk factors for Dry Eye due to hormonal changes. Women who receive postmenopausal estrogen replacement therapy are at increased risk of experiencing Dry Eye symptoms.2,4
Omega-6 fatty acids can cause the inflammation linked to Dry Eye, whereas omega-3 fatty acids may have anti-inflammatory effects. A diet that is low in omega-3 essential fatty acids or that has a high ratio of omega-6 to omega-3 fatty acids may increase the risk of Dry Eye.
Foods that contain omega-3 fatty acids include: fish and fish oils (salmon, mackerel, halibut, sardines, tuna, herring) as well as plants and their oils (canola oil, flax seed and flax seed oil, walnuts and walnut oil). Omega-6 fatty acids can be found in vegetable oils (margarine, mayonnaise, or other creamy salad dressings), butter, and nuts, such as peanuts.2,10
Vitamin A Deficiency
There are three components of the tear film: mucous, water, and oil. Goblet cells are special cells in the surface of the eye that produce the mucous that allows the watery layer to spread evenly over the surface of the eye. Mucous also helps the tears to stay on the eye. A lack of vitamin A can lead to Dry Eye because it is essential for the development of goblet cells. This condition can result from inadequate nutrition or from problems absorbing the vitamin. Sources of vitamin A include: cheese, milk, eggs, fish, leafy green vegetables, liver, and orange fruits and vegetables.1,11
- The Tear Film & Ocular Surface Society. 2007 Report of the International Dry Eye WorkShop (DEWS). Special Issue. The Ocular Surface 2007;5(2):67–204.
- Jackson WB. Management of dysfunctional tear syndrome. Can J Ophthalmol 2009;44(4):385–394.
- American Optometric Association. What women need to know about their eyes: omega-3s might help dry eye syndrome. Accessed at: www.aoa.org/x13399.xml on April 17, 2011.
- Ontario Association of Optometrists. Pregnancy and your eyes. Accessed at: www.optom.on.ca/for_patients/women_and_eye_health/pregnancy_and_your_eyes on April 3, 2011.
- Nettune GR and Pflugfelder SC. Post-LASIK tear dysfunction and dysesthesia. The Ocular Surface 2010;8(3):1335–145.
- National Eye Institute. Facts about cataract. Accessed at: www.nei.nih.gov/health/cataract/cataract_facts.asp on April 3, 2011.
- Cornea & Contact Lens Society of New Zealand Incorporated. Meibomian gland dysfunction. Accessed at: www.contactlens.org.nz/extra1.aspx on April 3, 2011.
- Ramamoorthy P, Sinnott LT, Nichols JJ. Contact lens material characteristics associated with hydrogel lens dehydration. Abstract. Ophthalmic Physiol Opt 2010;30(2):160–166.
- National Eye Institute. Facts about dry eye. Accessed at: www.nei.nih.gov/health/dryeye/dryeye.asp on April 14, 2011.
- Miljanovic B, Trivedi KA, Dana MR, et al. Relation between dietary n-3 and n-6 fatty acids and clinically diagnosed dry eye syndrome in women. Am J Clin Nutr 2005;82:887–93.
- Health Canada. Food and nutrition: vitamin A. Accessed at: www.hc-sc.gc.ca/fn-an/label-etiquet/nutrition/cons/vit-a-eng.php on April 17, 2011.