What Is It?
Allergies can affect various organs, including the eyes. Symptoms include itching, redness, lid swelling, tearing, light sensitivity, "grittiness" and swollen eyes.
While most people associate allergies with runny noses, sinus congestion, hacking and sneezing, in fact allergies can affect various organs, including the eyes. Because the eyes are often a significant component of your allergies, they deserve specific attention and treatment.
Many who have ocular allergies experience itching as the primary source of discomfort, though some people have no itchiness but instead experience a burning sensation and "eye fatigue" that causes them to rub their eyes. Other common symptoms include redness, lid swelling, tearing, light sensitivity, "grittiness" and swollen eye. On the other hand, if you have dryness, stinging and the feeling that there is a foreign body in your eye, you likely have dry eye syndrome.
Beyond being annoying, ocular allergies may be disabling. Allergic symptoms typically occur when allergy sufferers are in situations that put them in close contact with allergens to which they are sensitive, such as mowing the lawn, spending time outdoors or playing with pets. Thus, it can affect your ability to engage in these activities, as well as your efficacy at work and school. Beyond activities, however, appearances may become a major quality of life factor. For allergy sufferers, red eyes and puffy eyelids can be bothersome because they give the appearance of fatigue or perhaps even illness or substance abuse.
Dry eye sufferers typically feel "tired eyes." Their symptoms affect them most in computer work, reading or TV watching.
Eye allergies are anything but rare. In the United States, an estimated 20 percent of the population suffers from them, and the incidence appears to be on the rise. Some researchers believe that our increasingly clean, modern society--which no longer requires our bodies to fight off multiple childhood infections--has caused our immune systems to shift from an infection-fighting stance to more of an allergic stance. (Infection-fighting and allergies are opposites as far as the immune system is concerned). When the body's immune system becomes sensitized and overreacts to substances such as seasonal pollens and pet allergens, an allergic reaction can occur whenever they come in contact with your eyes.
So while many people enjoy the spring and fall, millions of others frequently live in dread of those times when the trees, grass and weeds begin to pollinate. People who are sensitive to these allergens experience seasonal allergic conjunctivitis, the most common type of eye allergy. Conjunctivitis refers to a part of the eye called the conjunctiva that becomes inflamed when triggered by an allergen. All the signs and symptoms of allergy--itching, redness, tearing and inflammation--occur when someone who is sensitive is exposed to allergens such as pollens, molds, house dust mites, animals and insects.
The reason the eyes are so sensitive to these substances is that they, like the skin, are exposed, unprotected surfaces that are especially vulnerable to allergens and other irritants. Allergens cause cells in the eye, called "mast cells," to release histamine and other substances or chemicals that cause blood vessels to dilate, mucous membranes to itch, and the eyes and eyelids to become inflamed. Tearing may also occur. Symptoms can range from mild eye annoyance to severe itching with major effects on the tissues inside the eyes. When the blood vessels expand, this allows for a greater flow of inflammatory and allergic molecules from the bloodstream into the eye, the site of the allergic reaction. This causes the redness and swelling of the eye. The itching is triggered by histamine binding to nerve cell receptors.
To avoid allergens, some patients have to stay indoors and lose time from school or work. Yet taking shelter is not always the answer. Some people must be outdoors for work or other daily activities. Additionally, some allergens reside indoors. Pet dander, dust mites and molds are common indoor allergens that can trigger symptoms for some people year round, causing perennial allergic conjunctivitis.
There are several more severe, although rare, forms of allergy, such as atopic keratoconjunctivitis (AK) and vernal keratoconjunctivitis (VK). These conditions may lead to corneal ulcers. However, the vast majority (80 to 90 percent) of eye allergies are caused by seasonal and perennial allergic conjunctivitis.
Ocular allergies may be further classified as either acute or chronic. An acute reaction occurs with intermittent exposure to an allergen, such as is often the case with seasonal allergic conjunctivitis, which may occur only at the height of pollen season. Chronic reactions occur with persistent exposure to allergens and are more likely to occur in perennial allergic conjunctivitis.
To make the diagnosis, your eye care professional must identify the type of allergic condition you are experiencing. The eye care professional begins by asking you questions to create a thorough medical history for you and to rule out the possibilities of other eye problems. In particular, your doctor will ask you to describe your symptoms and when they occur most frequently. The main indication of ocular allergies is itching, often accompanied by redness, swelling of the conjunctiva (the transparent membrane covering the eyeball and undersurface of the eyelid), eyelid swelling, light sensitivity, "grittiness," and sometimes tearing or mucus. Some people have no itchiness but experience a burning sensation and "eye fatigue" that causes them to rub their eyes.
The health care professional will examine your eyes thoroughly, looking for some of the classic signs of ocular allergy: fluid inside certain tissue layers in the eyes, more than normal visible redness of the blood vessels in the eyes, droopy or puffy eyelids and mucus discharge. In some people, congestion of the blood vessels in and around the eyes can cause dark circles to form around the eyes, called "allergic shiners." Eyelid swelling is also a sign of seasonal allergic conjunctivitis that can have permanent effects on the skin surrounding the eye. The acute reaction can cause rapid swelling and gradual "deflation," which, over time and repetition, can damage the collagen fibers and thin skin surrounding the eye, lending the appearance of drooping, wrinkly or sagging eyelids.
Many people also have itchy and runny noses. Some doctors may take a sample of your eyes' tears for laboratory analysis to help identify what is causing your eyes to have an allergic response. It is important for the doctor to determine that you are indeed having an allergic reaction. Other eye problems can cause similar symptoms, including viral or bacterial conjunctivitis, dry eyes or a condition called blepharitis, which occurs when tiny oil glands located near the base of the eyelashes malfunction. If you do not respond to treatment, you should be treated by a specialist such as an allergist/immunologist or an ophthalmologist.
Although the seasonal and perennial allergic conjunctivitis discussed above are the most common types of eye allergies, there are also four other types, which, as mentioned above, are rare. While seasonal and perennial allergic conjunctivitis represent 80 to 90 percent of ocular allergy cases, the severe forms described here make up the remaining 10 to 20 percent.
Vernal keratoconjunctivitis usually occurs in adolescent boys, with symptoms first appearing between the ages of 3 and 20. It is typically a seasonally recurring disease, not typically present perennially. Often, children who suffer from eczema, asthma or sinus allergies will find themselves experiencing eye allergies as well. The symptoms are similar but more severe than those of allergic conjunctivitis, including intensely itchy eyes that burn and feel as if something has entered the eye to irritate it. Light sensitivity and blurred vision may be present. This condition is considered to be potentially vision threatening.
Atopic keratoconjunctivitis usually occurs in adults who are highly sensitive to allergens and is associated with asthma, rhinitis, skin rashes or food allergies. Patients usually have the same signs and symptoms as those with the more common types of eye allergies, except that these patients have perennial inflammation and are at risk for cataracts or conjunctival and corneal scarring. There is usually lid swelling, particularly on the lower lid, and the skin is scaly and wrinkled. Corneal ulcers may form.
Contact lens-associated papillary conjunctivitis, also called giant papillary conjunctivitis, or GPC, is a reaction to ill-fitting contact lenses, contact lens overuse or to their solutions. People who wear disposable or gas permeable lenses are less likely to develop this reaction. It is not a true allergy. Early symptoms include blurred vision from the accumulation of deposits on the contact lens surface, itching and mucus discharge from the eyes, especially following sleep. Over time, you may be unable to tolerate the lenses in your eyes.
Contact ocular allergy or toxic keratoconjunctivitis can result from a reaction to medications used in or around the eye, such as antibiotics and antivirals and other medications. It may also result from other types of substances, such as preservatives in some eyewashes and eyedrops, or from chemicals found in cosmetics and hair spray, when used excessively. Fluid in and around the eye is a typical sign, and the skin around the eyes and eyelids may show signs of an allergic reaction (redness, puffiness and/or vertical wrinkles). Symptoms improve when you stop using the product that is causing the problem.
The treatment of ocular allergies is based largely on the degree to which symptoms interfere with quality of life. The more severe the symptoms, the more likely they are to interfere with everyday activities. The first step is to be evaluated by an allergist to identify the allergens causing your symptoms and to be educated by the allergist on how to avoid or remove the allergens that are creating the problem.
Some people find that applying cold compresses to the eyes is very soothing. That's because the compresses cause vasoconstriction, or a reduction of inflammation in the eye's blood vessels. Artificial tears, cooled by storing in a refrigerator, might produce similar results. It may also be necessary to avoid wearing contact lenses. Treating any associated eyelid problems, such as rashes or eczema, with lid scrubs and topical antibiotics may also help.
It may be necessary to get symptoms under control quickly by using a more aggressive approach. Following is a list of medications that are sometimes used.
Artificial tears are extremely safe and can be used at any age. The use of lubricants or saline washes helps to remove allergens from the eye's surface to relieve mild symptoms. However, artificial tears contain no pharmacologically active ingredients to specifically combat the allergic reaction. Instead, these products mimic the soothing properties of natural tears and provide fast relief. If your eyes are especially sensitive, you might consider using preservative- free products, which may be helpful for patients complaining of both allergy and dry eye symptoms or "itchy, burny" eyes.
Over-the-counter eyedrops, which frequently contain decongestants and antihistamines, are used by many people for short-term relief of some symptoms. They also help to reduce redness by constricting conjunctival blood vessels. However, they may not relieve other symptoms. Another shortcoming is that some may only be used for short periods, no more than four times a day for no more than two to three days. Prolonged use may worsen your symptoms, causing more swelling and redness that persists even after you stop using the drops. Tachyphylaxis, or a rebound effect, sometimes occurs with the use of other decongestants as well, such as nasal sprays. Although initially they seem to relieve stuffiness, after a few days your nose feels stuffier than ever. It's especially important to note that if you have heart disease, arteriosclerosis or narrow angle glaucoma, some eyedrops may pose a danger to your health. Nonsteroidal anti-inflammatory eyedrops may also work to relieve the itching associated with ocular allergies. You may need to use these drops four times a day, however, and they may cause burning or stinging when you first put them in your eyes. Your health care professional can tell if the solutions you are using might jeopardize your health or worsen your condition.
Over-the-counter oral antihistamines, available in both liquid and pill forms, can relieve itching slightly, but at the same time may cause dry eyes, worsening eye allergy symptoms. Side effects are sometimes very unpleasant and can include drowsiness, agitation, dizziness or poor coordination. These should not be used as primary therapy for ocular allergy. Direct, topically applied ophthalmic medication is a much better treatment. If you're taking over-the-counter oral antihistamines for nasal symptoms, consider adding an eyedrop to adequately address eye ocular complaints. An eyedrop can aid in treatment of nasal symptoms as well.
Antihistamines are available in both oral and topical forms. Topical antihistamines come in the form of eyedrops and are sometimes preferred over oral forms because they are applied directly to the eye and act more rapidly. Eyedrops are less likely to cause side effects because they are not taken into the body systemically as oral medicines are. Antihistamines provide quick relief, though sometimes only for a few hours. Some of the oral prescriptions are formulated to be non-sedating and so do not cause the drowsiness of over-the-counter formulations, but they still can cause some drying effect on the eyes, contributing to or worsening symptoms of dry eyes. Some topical antihistamines need to be reapplied four times a day. They last about two hours, but shouldn't be taken more than four times a day, so it could be difficult to get daylong coverage for your allergies if you're relying solely on ophthalmic antihistamines.
Combination mast cell stabilizers and antihistamines are the most recently developed drugs available for topical ophthalmic treatment of allergic conjunctivitis. They combine the mechanisms of both an antihistamine and a mast cell stabilizer in a single drug. This allows for rapid blocking of the histamine receptors on nerves and blood vessels that are the cause of the itching and redness of allergy, as well as stabilizing the mast cells to prevent further release of substances/molecules that would induce further allergic reaction. Dosing is typically two times a day. Drugs in this class include olopatadine (Pataday, Patanol), azelastine (Optivar) and nedocromil (Alocril, Lastacaft).
Second-generation mast cell stabilizers work to prevent those cells from releasing the substances responsible for itching and, if chosen as allergy therapy, must be used regularly to prevent problems in people with seasonal allergic conjunctivitis. Mast cell stabilizers are not thought of as a fast-acting choice for allergic conjunctivitis. In fact, it usually takes two weeks, using them twice a day, before they reach their peak effectiveness. Additionally, they require regular, consistent dosing throughout the allergy season, not just when an acute attack occurs.
Corticosteroids tend to be prescribed carefully, using the minimum dose and mildest type of steroid for the shortest possible time. One topical corticosteroid, loteprednol etabonate (Alrex, Lotemax), is prescribed when a rapid response to treatment is necessary and other drugs have not worked. Corticosteroids should never be used for any length of time, as they have been linked to cataracts, glaucoma and superinfections of the eye's surface.
Allergy shots, or immunotherapy, are sometimes used when other therapies do not help control your symptoms. These shots inject increasing amounts of the allergens that are affecting your eyes into your body to help curb your eyes' reaction. The treatment usually takes several months to achieve maximum results.
Selecting the Proper Treatment
Your health care professional will recommend or prescribe the medication needed to treat the symptoms that are most troublesome to you. The most common and most effective medications used to treat ocular allergies are topical--that is, they are applied as eyedrops directly to the surface of the eye. Topical medications offer several advantages. They are noninvasive and deliver medication directly to your eyes where it can be speedily absorbed. This also reduces the risk of side effects within other parts of your body because the drug is not absorbed throughout your system the way an oral drug would be. The effect of a topical eyedrop depends on several factors, including the size of the drop, the size and condition of the eye and your willingness to consistently use it as directed.
Some medications are safe for children but others are not, so be sure to read the packaging information carefully before offering your children any type of medication. Medication available by prescription should, of course, be used only by the individual to whom it was prescribed and not shared with any others.
Your health care professional may recommend more than one medication for you. In that case, be sure to administer eyedrops or ointments at least five minutes apart to allow enough time for your eyes to absorb each medication and to prevent one drug from diluting the other. In addition, contact lens wearers should carefully follow instructions regarding medication instillation prior to lens insertion, typically a 15-minute wait between medication and lens insertion. If you are using a solution and an ointment, use the solution first, followed by the ointment, since an ointment can prevent the drops from entering the eye.
The best way to prevent eye allergies is to avoid the source of the allergen. Once you and your eye care professional identify what substances are triggering your allergies, you can take steps to reduce contact with them. Take the following environmental control measures to minimize contact with pollens, molds and other substances.
1. Close windows and doors.
2. Avoid window or attic fans.
3. Reduce outdoor exposure to allergens by staying indoors when allergens are at their peak, usually in the morning.
4. Shampoo and shower following outdoor exposure to allergens.
5. Stay away from damp areas, such as a basement, that may harbor molds.
6. Avoid lawn mowing or raking leaves.
7. Minimize humidifier use to reduce the spread of molds.
8. Wash bedding in very hot water (at least 130 degrees F) frequently and dry in a hot dryer so that dust mites don't proliferate. Use allergen-proof covers for pillows, mattresses and box springs.
9. Stay away from curtains or drapery that may harbor dust.
10. Remove stuffed toys from children's reach.
11. Avoid furry animals.
12. Avoid irritants such as tobacco smoke, perfume, potpourri, chalk dust and markers.
You can take a number of additional measures. For example, try not to rub your eyes, even though they may itch horribly. Rubbing the eyes can worsen the allergic reaction. Your condition may clear up more quickly if you don't rub.
Facts to Know
1. Twenty percent of people in the United States suffer the discomfort of eye allergies.
2. Steroids are sometimes used to treat eye allergies, but they carry a much greater risk of short- and long-term side effects than other therapies, including risks for glaucoma and cataracts. Steroid use should be reserved only for cases that do not respond to other treatment and for severe forms of allergy.
3. The most effective way to treat the eye is with eyedrops. If you're taking a pill for nasal allergy symptoms, consider adding eyedrops to more effectively and specifically treat the ocular complaint.
4. Combination mast cell stabilizers and antihistamines, which combine mechanisms of both antihistaminic and mast cell stabilization in a single drug, are the most recently developed drugs for topical treatment of ocular allergies.
5. More and more people seem to be suffering from allergies these days. The exact reason why is unclear, but some researchers believe that our clean, modern society no longer requires us to fight off multiple childhood infections, thus causing our immune systems to take on a more of an allergic stance.
Questions to Ask
Review the following Questions to Ask about ocular allergies so you're prepared to discuss this important health issue with your eye care professional.
1. How can I prevent my ocular allergies?
2. What are the specific allergens that are causing my problem?
3. How can I tailor my activities to avoid those allergens?
4. What type of medications will relieve the itching in my eyes?
5. Can my children safely use eye allergy treatments?
6. Will eye allergies affect my vision?
1. What are ocular allergies?
Common things in the environment such as dust or pollen irritate some people's eyes. These substances are called "allergens," and they can cause symptoms such as itching and swelling in the eyes. This reaction is usually centered in a part of the eye called the conjunctiva, which becomes inflamed when triggered by a substance that a person is especially sensitive to. An ocular allergy can happen suddenly or some time after you come in contact with the allergen.
The most common form of ocular allergy is seasonal conjunctivitis. When a susceptible person is exposed to allergens from the environment, such as pollens in the fall and spring, they experience seasonal conjunctivitis. However, some people suffer year round from perennial allergies caused by other substances such as molds, house dust mites, animals and insects. They may have chronic allergies, which occur with persistent exposure to allergens, or acute attacks from intermittent exposure to these triggers.
2. Are there any other types of eye allergies besides seasonal and perennial?
Yes, though these severe forms of ocular allergy are rare. Vernal keratoconjunctivitis usually occurs in adolescent boys who suffer from eczema, asthma or sinus allergies. Atopic keratoconjunctivitis usually occurs in adults who are highly sensitive to allergens associated with asthma, rhinitis, skin rashes or food allergies. Contact lens-associated papillary conjunctivitis appears to be an allergic reaction to contact lenses or their solutions. Contact ocular allergy or toxic keratoconjunctivitis can result from a reaction to medications used in the eye, such as antibiotics and antivirals.
3. What happens when allergens affect the eyes?
When your eyes come in contact with something your body considers foreign--such as pollen, dust or pet dander--special cells in your eyes go on alert. These cells then release different kinds of chemical substances that can cause your eye allergy symptoms. This does not happen in all individuals, but only those who have been "sensitized" to these specific foreign substances.
4. Can cigarette smoke cause eye allergies?
Although cigarette smoke, diesel exhaust and other environmental substances may cause your eyes to become inflamed and irritated, they do not trigger an allergic response. But they can make your allergy symptoms worse.
5. How do I know if I have eye allergies?
Itching is the symptom that allergy sufferers complain about most. Other common reactions are redness and watery eyes. You may also have swelling, puffiness or throbbing. Some people find that their allergies make their eyes very sensitive to light. However, they only way to be certain that you are having an allergic response instead of some other type of eye problem is to visit your eye care professional for a diagnosis.
6. How can I prevent eye allergies?
The best way to prevent eye allergies is to avoid the source of the allergen. Once you and your health care professional identify which substances are triggering your allergies, you can take steps to reduce contact with them.
7. The nonprescription medicines I am buying are not helping enough. What else can I do?
Many new therapies are available to help relieve the symptoms of eye allergies and even to prevent them. Discuss the options with your eye care professional, who can tell you which medication is best for you.
8. What is the most common treatment for eye allergies?
An effective allergy medication specifically aimed at halting ongoing symptoms and preventing future symptoms of allergy is best. Today, this would be the dual-action agents (antihistamine/mast cell stabilizers).
Topical antihistamines, usually in combination with decongestants, are another treatment option. They act quickly and effectively to block allergen receptors. However, they may need to be used up to four times a day.
9. Do allergy shots help eye allergies?
Allergy shots, or immunotherapy, are sometimes used when other therapies do not help control your symptoms. However, they can take months to work and therefore are not typically the first choice for treatment.
1. Too blue to hide inside?
If your eye allergies are triggered by pollen, staying inside all day long may not be the answer. There are other ways to evade the offending pollen. You can remain indoors during the times of day that the pollen levels are highest--usually mornings or on especially sunny, windy days. If you have pollen-triggered allergies but your job requires you to work outside, you can wear a face mask designed to filter out pollen and keep it from reaching their nasal passages. Some people schedule vacations around pollen season, taking themselves out of harm's way for some fun and relaxation at the beach. The avoidance of allergens is typically not practical though, so most allergy sufferers will turn to the use of effective prescription medications.
2. Beware of side effects
Many people who take systemic antihistamines experience some distressing side effects: drowsiness, dry eyes and loss of alertness and coordination (although, in newer generations of these systemic antihistamines, some side effects such as drowsiness have been minimized). In children, such reactions can be misinterpreted as behavior problems. If your teddy bear youngster begins to behave more like a grizzly, it could be a reaction to antihistamine medications. More effective and less troublesome medications might be a better choice.
3. Does your pet make you cry?
Nearly any pet can cause allergies, including ocular ones. For people who are especially sensitive to them, pet dander, skin flakes, saliva and urine can cause your eyes to tear, burn and itch. Another big source of discomfort for pet owners with eye allergies is the pollen, mold spores and other outdoor allergens brought inside on your animal's fur. If you can't bear to give up your fur-bearing friend, try these strategies to minimize your allergies:
** Keep your pet out of your bedroom, where you spend the most time.
** Wash your hands after handling your pet to avoid spreading the dander.
** Have someone else bathe your pet weekly and brush it outdoors several times a week.
** Ask someone else to clean the litter box and store it away from forced air heating or central air conditioning vents.
4. It's more than just dust
People whose eye allergies are perennial are likely sensitive to dust and other allergens. But did you know that so- called "house dust" is actually a varied mixture of potentially allergenic materials? It may contain fibers from different types of fabrics; cotton lint, feathers and other stuffing materials; dander from cats, dogs and other animals; bacteria; mold and fungus spores (especially in damp areas); food particles; bits of plants and insects; and other allergens. House dust also contains microscopic mites. These mites live in bedding, upholstered furniture and carpets. In a warm, humid house, mites continue to thrive even in the coldest months. That's why it's important to vacuum frequently and to wash your bedding in hot water (at least 130 degrees F). Try to keep your thermostat turned down, to the extent that it remains comfortable. Creating a humid, tropical environment will only breed more problems.
5. Tips for Using Eye Drops
Making sure the drops stay in the eyes instead of dripping down your face is more a matter of method than luck. The American Academy of Allergy, Asthma & Immunology offers the following suggestions:
** Wash your hands.
** Rotate the bottle around gently for 30 to 40 seconds before inserting drops.
** Tilt your head back.
** Pull your lower eyelid away from your eye, either by pulling downward with one finger or by pinching your lower lid into a slot where the drop may be inserted.
** Let the medicine fall from the bottle's dropper into the pocket; do not touch the dropper against your eye or anything else.
** If more than one drop has been ordered, wait three to four minutes before putting another drop into the same eye.
** Replace the cap immediately after use to keep the medication clean.
** Wipe excess liquid with a tissue.
** Wash your hands.
Organizations and Support
For information and support on coping with Ocular Allergies, please see the recommended organizations and Spanish- language resources listed below.
American Academy of Ophthalmology
Address: P.O. Box 7424
San Francisco, CA 94120
National Eye Health Education Program
Address: National Eye Institute Information Office
31 Center Drive MSC 2510
Bethesda, MD 20892
Ocular Immunology and Uveitis Foundation
Address: 348 Glen Road
Weston, MA. 02493
Phone: 617-494-1431, Ext. 112
Schepens Eye Research Institute
Address: 20 Staniford Street
Boston, MA 02114
American Academy of Allergy Asthma & Immunology
Address: American Academy of Allergy, Asthma & Immunology
555 East Wells Street, Suite 1100
Milwaukee, WI 53202
National Eye Institute
Address: National Eye Institute
2020 Vision Place
Bethesda, MD 20892
"Eye Allergies." The American College of Allergy, Asthma & Immunology. June 2009. http://www.acaai.org/patients/resources/allergies/Pages/eye-allergies.aspx. Accessed November 2010.
"Ocular allergies." By Clifford W. Bassett, MD, FAAAAI. The American Academy of Allergy, Asthma, & Immunology. 2007. http://www.aaaai.org. Accessed July 2008.
"Allergic conjunctivitis." Uptodate.com. Last updated February 2008. http://www.uptodate.com. Accessed July 2008.
"Tips for administering eye drops." The American Academy of Allergy, Asthma, & Immunology. http://www.aaaai.org. Accessed July 2008.
"Vernal Keratoconjunctivitis (VCK)." The University of Michigan Kellogg Eye Center. 2008. http://www.kellogg.umich.edu. Accessed July 2008.
"Atopic Keratoconjunctivitis." The University of Michigan Kellogg Eye Center. 2008. http://www.kellogg.umich.edu. Accessed July 2008.
"Why are allergies becoming more common?" by Daniel More, MD. Updated November 20, 2007. http://allergies.about.com. Accessed October 2008.
Akpek EK. Ocular Allergy. Available at: http://www.uveitis.org. Accessed December 17, 2002.
American Academy of Allergy, Asthma, and Immunology. Eye Allergies: Believe your eyes, and see what they may be telling you. Available at: http://allergy.mcg.edu. Accessed December 17, 2002.
American Academy of Allergy, Asthma, and Immunology. Ocular Allergies, February 2001. Available at: http://www.aaaai.org. Accessed December 17, 2002.
Bielory L. Update on ocular allergy treatment. Expert Opinion on Pharmacotherapy 2002;3(5):541-553.
Gross RD. Ocular allergy signs, symptoms best handled after specifics answered. Ophthalmology Times May 1, 2002.
Schmid KI, Schmid LM. Ocular allergy: causes and therapeutic options. Clin Exp Optom 2000;83:5:257-270.
Abelson MB, Udell IJ. H2 receptors in the human ocular surface. Arch Ophthalmol 1981;99:302-304.
Abelson MB, Chambers WA, Smith LM. Conjunctival allergen challenge: a clinical approach to studying allergic conjunctivitis. Arch Ophthalmol 1990;108:84-88.
Abelson MB, Chapin MJ, Current and Future Topical Treatments for Ocular Allergy. Comp Ophthalmol Update 1:2000, 303- 320.
Spangler DL, Abelson MB, Ober A, Gomes PJ. Randomized, Double-Masked Comparison of Olopatadine Ophthalmic Solution, Mometasone Furoate monohydrate Nasal Spray, and Fexofenadine Hydrochloride Tablets Using the Conjunctival and Nasal Allergen Challenge Models. Clinical Therapeutics 25(8); 2003, 2245-2267
Abelson MB, Pratt S, Mussoline JF, Townsend D. One-Visit, Randomized, Placebo-Controlled, Conjunctival Allergen Challenge Study of Scanning and Imaging Technology for Objective Quantification of Eyelid Swelling in the Allergic Reaction with Contralateral Use of Olopatadine and Artificial Tears. Clinical Therapeutics 25(7); 2003, 2070-2084.
Abelson MB, Smith L, Chapin M. Ocular Allergic Disease: Mechanisms, Disease Sub-types, Treatment. The Ocular Surface 1(3); July 2003, 127-149.