strategic skill builders

Maximize Contact Lens Success During Allergy Season

Help contact-lens wearers achieve comfort and maintain wear during these difficult seasons.

JOEL A. SILBERT, O.D., F.A.A.O., PHILADELPHIA

For many contact-lens wearers, allergy season is a time of dread. With the advent of spring and then summer and both seasons' attendant production of new flowers, grasses and airborne pollen, many patients are significantly challenged by allergic rhinitis (nasal congestion, runny nose, sneezing, watery eyes and itchy nose and eyes) and seasonal allergic conjunctivitis (SAC) (ocular discomfort, itchy eyes, eye redness and watery eyes).

In fact, allergies have become so pervasive, that estimates now indicate that nearly 50 million people are affected in the United States alone. And, approximately 4%, or 2 million of these allergy sufferers, have eye allergies as their primary allergy.¹

Because the majority of allergic patients have ocular symptoms that may necessitate the use of oral and/or topical prescription medications, as well as over-the-counter (OTC) products, it should come as no surprise that quality-of-life issues rank high for this group.^2-3

Also, because these ocular symptoms are so troublesome, patients with SAC may assume they can't wear contact lenses and thus never bring up the idea with you. For those allergic patients who do wear contact lenses during these seasons, the most common complaint is a reduction in wearing time due to allergic symptoms, which necessitates the use of spectacles and OTC products to achieve relief.

As is often the case, practitioners tend to minimize patient concerns regarding their ocular symptoms and prescribe medications infrequently. In fact, most topical ocular allergy medication prescriptions are written by allergists, rather than by eye-care practitioners.⁴

As a result, most O.D.s advise their allergic patients to give up lens wear during allergy season. This is often unnecessary, however, as judicious use of specific ocular medications, as well as switching to other types of contact lenses for limited periods during times of heightened allergic symptoms, or permanently, may allow these patients to continue wearing contact lenses and improve their overall quality-of-life.

Here, we'll examine the mechanisms that cause seasonal ocular allergy, the differences between SAC and perennial allergic conjunctivitis (PAC), some management guidelines you should consider and available pharmacologic relief for these patients.

MECHANISMS OF SEASONAL OCULAR ALLERGY

Ocular allergy is a consequence of the body's host defense mechanisms, which are designed to protect against foreign microorganisms and environmental threats. These defense mechanisms may include:⁵

• anatomic barriers (such as the skin or, in the eye, the corneal epithelium and Bowman's layer)

• physiologic barriers (such as the tears, by their flushing action, their associated antimicrobial substances and by their mucin entrapment of pathogens)

• phagocytic barriers (such as leukocytes, which attack, ingest and destroy bacteria)

• the immune response (by production of specific antibodies that respond to foreign substances or antigens)

• the inflammatory response (increases vascular permeability and blood flow so that antibodies, leukocytes and chemical mediators can attack, limit and destroy pathogens).

Although immune reactions and inflammatory responses protect the body against infection, their actions can lead to host tissue damage. "Hypersensitivity" is the term clinicians use to describe such damage that occurs in response to foreign antigens. This may be a short-term response, or allergy, or a long-term disease response (such as in autoimmune disease from the body's own antigens).

SAC VS. PAC

SAC is a Type-I hypersensitivity reaction. These allergic reactions occur quickly (within minutes) as a result of exposure to an antigen to which the body has been pre-sensitized via prior exposure. Type-I reactions are sometimes termed "immediate" or "anaphylactic" reactions. Antigens involved in Type-I reactions may be airborne (pollens), associated with food, such as eggs, drugs, such as penicillin, or even insect bites, such as a bee sting. Local examples of Type-I reactions are the symptoms of SAC (itching, redness, tearing), hay fever (allergic rhinitis) and asthma, food allergies and atopic dermatitis.⁵

PAC produces antigens that are more widespread and chronically present than SAC. This results in a year-round Type-I allergic response (such as from dust mites, mold and pet dander).

Patients with SAC or PAC have similar clinical ocular presentations, including bilateral itching, foreign-body sensation, burning, stringy mucus production and occasionally chemosis of the bulbar conjunctiva. The clinical difference between the two: Patients with PAC often have "atopic" allergy, which refers to an inherited predisposition to develop allergic responses. Although PAC symptoms are year-round, they may worsen in allergy season and are often associated with asthma.

Type-I hypersensitivity reactions are typically mediated by immunoglobulin E (IgE), which forms in response to allergens. The conjunctiva contains more than 50 million mast cells. When IgE binds to the mast cell, after re-exposure to the antigen, there is an influx of calcium ions, resulting in degranulation of the mast cell's preformed histamine and chemotactic factors. The release of histamine causes itching via nerve stimulation (H1 receptors on nerve endings). Phospholipase A2, contained within the walls of the mast cell, is liberated as well, which ultimately leads to the production of arachidonic acid and platelet-activating factor (PAF). This in turn is converted, via the cyclo-oxygenase pathway, into prostaglandins, thromboxanes and other inflammatory mediators involved in the early phase of the immediate response, which can last up to a few hours.⁵ Mast cell-stabilizers can prevent the influx of calcium ions into the mast cell, preventing degranulation.⁶

Late phase reactions may occur with the presence of eosinophils, which can begin from three to 12 hours after first exposure to the offending antigen. This phase may last for many hours and is responsible for the release of additional mediators that give rise to vasodilation (redness), increased vascular permeability, increased mucus secretion, pain and chemotaxis. Mast cell-stabilizers aren't always able to suppress these late-phase reactions. The lipoxygenase pathway converts arachidonic acid into leukotrienes (these cause smooth muscle contraction, chemotaxis and bronchoconstriction). Note that non-steroidal anti-inflammatory drugs (NSAIDs) can block the cyclo-oxygenase pathway, but not the lipoxygenase pathway. Corticosteroids, on the other hand, work higher up in the cascade and can block both phases of the arachidonic acid pathway as well as the PAF pathway.⁵ Note that SAC and PAC are both representative of early allergic response in their clinical manifestations. Late allergic response does not clinically manifest in either of these conditions.^7,8

MANAGEMENT GUIDELINES

With the previous background on seasonal allergy, how can we best manage our contact-lens patients and maximize their success during this difficult period? Here are some effective strategies:

• Instruct patients to avoid specific antigens. Although we cannot place our patients in a bubble, general avoidance of specific antigens, such as pollen, is helpful (although not always possible). To keep pollen away from the ocular surface, recommend the use of wrap-around and closely-fitted sunglasses for your contact-lens patients; tell patients that when in their car, they should run the air conditioner with the windows closed to keep antigens out; and instruct them to use the highest grade air filters for home air conditioning systems and replace them frequently. (For additional information on air filters and air cleaning systems, see: http://www.webmd.com/asthma/guide/do-you-need-an-air-filter. Also, tell Fido or Fluffy he (or she) can no longer spend time in your bedroom and certainly not on your bed. Pet dander is highly antigenic. Keep pets off the furniture too if at all possible. In addition, instruct your allergy patients to avoid morning and early afternoon outdoor activities when pollen levels are at their highest. Finally, suggest they let someone else mow the lawn, rake and vacuum, or have patients wear a mask if they can't delegate to a family member.

• Advise patients to dilute and flush antigens. Tell patients to use lubricating drops while wearing contact lenses to dilute and flush the antigens present on the lenses and the conjunctiva. Some OTC products not only lubricate lenses, but also provide an in-eye cleansing function of the lenses. Finally, advise patients to reduce pollen levels on their hands, face and hair by frequent hand-washing and shampooing, especially after having been outside. Antigens from both outdoor and indoor sources are present in large quantities in these exposed body parts and are transferred to pillows and bedding. To reduce not only these environmental antigens, but also the volumes of allergenic dust mites, be sure to wash pillowcases and sheets frequently and at the highest possible temperature.

The consequences to mast cell degranulation are many.

• Consider preservative-free disinfection systems. Many patients with ocular allergies do better when the eye isn't further challenged by chemicals. While many good multi-purpose solution systems are available today, the use of a hydrogen peroxide-based system may give the allergic patient a much better chance of success during allergy season and year-round due to reduced symptoms of discomfort and dryness found with the elimination of multipurpose solution preservatives and additives.⁹

• Rub or No-rub? Whether you choose a multi-purpose solution (MPS) system or a peroxide-based system, tell the allergic patient who wants to wear contact lenses to rub and rinse his lenses upon removal, prior to disinfection, for a better decrease in antigen load (even if the package description says "no-rub"). Peroxide system users need to obtain a preservative-free saline for this purpose, however. Lens rubbing reduces large volumes of bacteria and surface antigens. Additionally, the use of a surfactant cleaner can also be helpful in reducing antigenic load for allergic patients.

• Cold is gold. Tell the patient to use cold compresses to relieve itching and to avoid eye rubbing, as mechanical irritation can cause release of inflammatory mediators.

• The 'Daily Double.' Allergy sufferers who wish to successfully wear contact lenses should never wear lenses on an extended-wear basis. Perhaps the best management strategy, however, is to use a daily disposable contact lens. This is because a fresh lens worn every day provides the least stress for the allergic eye, with less antigenic load on lens surfaces and no need to use disinfection solutions. A fresh, sterile lens minimizes the effects of lens deposits, inadequate cleaning techniques and irregular lens surfaces, in addition to eliminating potential sensitivities to solution preservatives. Studies have shown that patients with significant SAC symptoms had less burning, hyperemia and tearing as well as better comfort with a daily disposable lens compared with their habitual contact lenses.^10,11

PHARMACEUTICAL MANAGEMENT

In addition to the tips mentioned above, pharmacologic agents can greatly assist the ocular allergy sufferer. As a general rule, contact-lens patients shouldn't use allergy medications while wearing their lenses. This is because the preservatives used in topical medications (typically, benzalkonium chloride) can cause corneal toxicity and staining if absorbed into hydrogel-lens materials. B.i.d. dosing is generally adequate for most agents, so putting a drop in the eye about 10 minutes prior to lens insertion, and again after lens removal should suffice. Topical eye medications are likely to produce greater relief of eye symptoms than that afforded by systemic allergy medications alone (which may help with other generalized allergy symptoms). Currently available options include:

• vasoconstrictors. Topical, OTC vasoconstrictors may provide temporary relief of itching and redness associated with SAC, but should be avoided with contact-lens wear, as these agents may mask hyperemia associated with inflammation, staining and edema. Additionally, vasoconstrictors may lead to rebound hyperemia with prolonged use, or possibly to anterior chamber angle narrowing in certain patients. These products may be found alone or in combination with mild antihistamines.¹²

This diagram explains the mechanisms of mast cell stabilizers.

• antihistamines. For patients who complain only of ocular itching, employ a simple antihistamine drop, along with cold compresses. However, most allergy sufferers have ocular signs and symptoms with SAC that go beyond simple itching.

• corticosteroids. Although quite effective, use topical corticosteroid drops with caution in contact-lens wearers, due to potential side-effects. For instance, since topical anti-allergy drugs are likely to be taken for several weeks to several months during allergy season, steroids could potentially elevate intraocular pressure (IOP) in select patients (with genetic predisposition as steroid responders). For shorter periods of use (a week or two to calm a very inflamed eye), this issue is rarely a problem. Nevertheless, monitor IOP whenever you prescribe steroids. Be aware that your allergy patients may also be taking nasal steroid sprays, which could further potentiate this side effect, so it's probably best not to use topical steroid drops with allergy patients for routine control of SAC allergies. Reserve their use only for short-term control of signs and symptoms when other pharmacologic strategies are ineffective. For contact lens wearers, use of the newer "soft steroids" is preferred over conventional topical steroids, as potential side effects are considerably lessened.¹²

• combination treatments. By far, the best drugs for relief of SAC symptoms, whether associated with contact-lens wear or not, are combination agents that have both antihistaminic as well as mast-cell stabilizing properties. They not only relieve itching, but also inhibit the production of inflammatory cytokines by the conjunctival epithelium, as well as synthesized inflammatory mediators from conjunctival mast cells. This category of drugs includes eyedrops with b.i.d. dosing, with the exception of olopatidine 0.2%, which is q.d.:

• Azelastine 0.05% (Optivar, Bausch & Lomb)

• Epinastine 0.05% (Elestat, Allergan)

• Ketotifen fumarate 0.025% (Zaditor, Novartis and Alaway, Bausch & Lomb) — both now OTC products

• Olopatidine 0.1% & 0.2% (Patanol & Pataday, Alcon).

Although allergy season can be very frustrating for allergy sufferers and especially for contact-lens wearers, you can employ a number of strategies to help these patients continue lens wear. While we won't be able to help everyone who has ocular allergies, we can help many when we give attention to specific issues. Avoidance and dilution of allergens, the use of daily disposable lenses and carefully chosen pharmacologic agents can help keep many of your allergy patients successfully wearing their lenses when Mother Nature says otherwise. OM

References furnished upon request.