allergy

Ocular Allergy: A Review

Brush up on the basics, so you can capture more medical patients.

Ernie Bowling, O.D., M.S., F.A.A.O., DIPL., Tuscaloosa, Ala.

Managing ocular allergy may not be as glamorous as managing age-related macular degeneration or glaucoma, but it can be just as personally and financially rewarding. The reasons:

► Tons of these patients exist and are desperate for relief. As many as 50 million individuals in the United States suffer from various forms of allergic conditions, and it is estimated that 50% of individuals with seasonal and indoor allergies experience some degree of ocular allergy.^1-3 To further break this down, ocular allergies affect one in every five individuals in the U.S.¹ Also, an estimated 70% to 80% of individuals in the United States who have seasonal allergic rhinitis experience severe ocular symptoms.² Keep in mind that as many as 95% of people with allergies are afflicted with allergic rhinitis.⁴

In addition, results from one study on seasonal allergy patients revealed that an estimated 8% experienced ocular symptoms alone, while 85% experienced ocular symptoms in conjunction with their nasal symptoms.⁵ Further, the study showed that a majority of the subjects reported their ocular symptoms were as severe or more severe when compared with their nasal symptoms. And, numerous recent reports indicate that both the incidence and prevalence of allergic conditions have increased dramatically through the past 40 years and continue to rise.⁶

► Treating ocular allergy patients grows the medical side of your practice. Several practitioners who have successfully diagnosed and treated these patients have reported time and time again that doing so has bound these patients to their practice for their other medical eyecare needs, increasing their practice's revenue. Keep in mind that allergies are not only extremely uncomfortable, but they also impede one's ability to go about their daily lives. So, when someone can offer these patients relief, you better believe, they're grateful. (See “Billing and Coding,” below.)

Here, let's review the types of ocular allergy, differential diagnoses and the currently available treatments, so you can successfully diagnose and treat these patients and reap the personal and financial rewards described.

The types

As the large majority of eye allergies involve the conjunctiva, the terms “ocular allergy,” and “allergic conjunctivitis” are often used synonymously. Allergic conjunctivitis is inflammation of the conjunctiva that is caused by an allergic reaction. Ragweed is the most common cause of allergic conjunctivitis accompanying allergic rhinitis, while grass pollen is more commonly thought to cause only ocular symptoms, such as itchy, watery eyes.⁷ Allergic conjunctivitis is the most common hypersensitivity response of the eye and is comprised of a group of diseases that affect the ocular surface. This group:

► Seasonal allergic conjunctivitis (SAC). SAC is the most common form of allergic conjunctivitis.⁷ The Symptoms: itchy eyes and/or a burning sensation. Symptoms are usually bilateral, but there may be asymmetric involvement. In addition, ocular symptoms are often accompanied by nasal and pharyngeal symptoms, such as a runny nose and scratchy throat. Associated symptoms are asthma (and/or eczema).⁷ The clinical signs: watery discharge, white exudates, which with chronicity become stringy, mild injection of the conjunctival surfaces with varied levels of conjunctival edema and papillary hypertrophy along the tarsal conjunctival surface.

The onset of symptoms is seasonally related to specific circulating airborne allergens. Grass pollens are associated with increased ocular symptoms during the spring and during “Indian summer” in the fall.

► Perennial allergic conjunctivitis (PAC). The prevalence of PAC, which is considered a variant of SAC, is much lower than that of SAC.⁸ In addition, although symptoms of PAC are the same as those of SAC, they tend to be less severe.⁹ Further, patients with PAC also have associated symptoms of asthma and/or eczema.⁷

Dust mites, animal dander and feathers are the most common airborne allergens implicated in PAC, which is more likely than SAC to be associated with perennial rhinitis.⁷

PAC persists throughout the year, although 79% of PAC patients have seasonal exacerbations.⁸

► Other allergic eye disease. Atopic keratoconjunctivitis (AKC); vernal keratoconjunctivitis (VKC); and giant papillary conjunctivitis (GPC) comprise only a small percentage of ocular allergies, though each tend to be more severe than SAC and PAC and can cause damage to the ocular surface.¹⁰ Specifically, AKC and VKC can compromise the cornea, causing ulcers and scarring and can ultimately lead to vision loss.¹¹

GPC is typically associated with the use of extended wear soft contact lenses, and, therefore, places patients who have allergies and wear these lenses at a greater risk for the condition.

Differential diagnosis

The differential diagnosis of ocular allergy includes other causes of acute red eye, such as acute anterior uveitis and infectious keratitis. The most common differential diagnosis of ocular allergy, however, is dry eye. It's important to be aware that the two conditions often coexist, as the dry eye patient typically does not produce enough tears to wash offending allergens out of the eye.

Patient history and clinical signs aid in the differential diagnosis. Dry eye patients present with signs of ocular surface disease as well as sodium fluores-cein staining of the cornea and conjunctiva.

Treatment

The treatment step ladder for allergic eye disease consists of educating the patient to avoid the offending allergen — if at all possible, non-pharmacologic treatments, pharmacologic treatments and if all else fails, referral to an allergist for possible immunotherapy.

► Avoiding triggers. Avoidance can be difficult, as many times the patient doesn't know the allergen trigger. That said, common triggers include dust mites and mold.

► Non-pharmacologic treatments. If dust mites trigger the patient's ocular allergy, recommend he purchase bedding and pillowcases that prevent their accumulation. Also, recommend he wash his sheets in hot water, and keep the home humidity level between 30% and 50%. Heat kills the mites. In addition, tell the patient he should clean his hard floors with a damp mop instead of sweeping, as sweeping stirs up dust.

If indoor mold is the trigger, instruct the patient to regularly clean his bathroom(s), kitchen and basement, as these are places where mold tends to lurk. Also, recommend the patient purchase a dehumidifier and clean it regularly. A high-efficiency particulate air (HEPA) filter can trap mold spores.

If the patient is a contact lens wearer, recommend he switch modalities for comfort or discontinue lens wear during acute ocular allergy episodes.

Regardless of the allergen, recommend cold compresses, as patients find the temperature quells the ocular allergy-associated itching and burning. (For this reason, all ocular medications generally provide more symptomatic relief if applied after refrigeration.)

► Pharmacologic treatments. When avoidance and non-pharmacologic strategies do not provide adequate relief, prescribe topical pharmacologic treatments to lessen the allergic response. Start with tear substitutes. These primarily assist in the direct removal and dilution of allergens from the ocular surface. If these are inadequate, prescribe an ophthalmic ointment to be used at bedtime to provide moisture to the ocular surface. Should this course of action be unsuccessful, consider prescribing topical decongestants, antihistamines, mast-cell stabilizers, mast-cell stabilizer/antihistamine agents and anti-inflammatory drugs.

Treat AKC, VKC and GPC — the more severe variants of conjunctivitis — with topical corticosteroids. Intranasal corticosteroids are very effective for treating nasal symptoms of allergic rhinitis, but little conclusive evidence shows they're effective for ocular symptoms.^12,11

Adjunctive topical agents have been found to be beneficial for allergic conjunctivitis patients who also use antihistamines.¹³

► Referal for immunotherapy. Patients who don't respond to topical and/or oral medications warrant a referral to an allergist for possible immunotherapy (or allergy shots). To many of us, the word “referral” means loss of patient to another healthcare provider. In this case, it can actually garner you referrals from the allergist in the future. After all, now that he knows you can identify and treat ocular allergy, he may need your expertise with one of his patients, and he'll likely tell his colleagues about you.

Just like Rome wasn't built in a day, you won't see an immediate surge in your medical patients as a result of diagnosing and treating ocular allergy. It will take time. But through persistence in identifying and attracting ocular allergy patients, you will get there a lot faster than those optometrists who choose to simply refer these patients to an allergist. You're the eyecare practitioner. Who better to treat ocular allergies than you? OM

1. Airborne allergens: Something in the air. National Institute of Allergy and Infectious Diseases. NIH Publication No. 03-7045. 2003.
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9. Chisholm-Burns M, Wells B, Schwinghammer T, et al. Pharmacotherapy Principles and Practice. New York: McGraw-Hill Medical; 2007:939-940.
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11. Bielory L, Katelaris CH, Lightman S, et al. Treating the ocular component of allergic rhinoconjunctivitis and related eye disorders. MedGenMed. 2007 Aug 15;9(3):35.
12. Bousquet J, van Cauwenberge P, Khaltaev N. Allergic rhinitis and its impact on asthma. J Allergy Clin Immunol. 2001; Nov;108(5 Suppl):S147-334.
13. Welch D, Ousler GW, Nally LA, et al. Ocular drying associated with oral antihistamines (loratadine) in the normal population — an evaluation of exaggerated dose effect. Adv Exp Med Biol. 2002; 506(Pt B):1051-5.

Dr. Bowling is in private practice in Tuscaloosa, Ala. He writes and lectures extensively on several eyecare topics, including ocular allergy and dry eye. E-mail him at drbowling@windstream.net. Or, send comments to optometricmanagement@gmail.com.