ALLERGY AND LENS WEAR
Ditch the Itch: Managing Allergy and Lens Wear
Lens wearers are often the most affected by allergy, but effective treatment will help keep them in lenses.
By Arthur B. Epstein, OD, FAAO, FBCLA, DPNAP
Some eyecare practitioners think of allergy as trivial and unimportant, an easily diagnosed and treated problem barely worthy of consideration. Others think of it as a seasonal nuisance. In truth, allergy is an exquisitely complex disorder that continues to grow in complexity with ongoing changes in our environment and demographic shifts. Effective allergy management is especially critical in contact lens wear in which even mild presentations can derail success.
Allergy represents a tremendous opportunity for interested clinicians. Effective treatments with near immediate symptom resolution make allergy therapy an essential building block of a successful therapeutic practice and an effective way to foster patient loyalty and trust.
If you think that allergy isn’t a major problem for your contact lens wearers, think about how frequently patients tell you that they can’t wear contact lenses because they have allergies. That’s only the tip of the iceberg. For every patient who tells you that he has stopped wearing his lenses, many more have also stopped and not taken the time or had the courage to tell you.
The Big Picture
Allergy affects about one-third of the U.S. population, with the eyes involved in as many as 80% of cases (www.cdc.gov/nchs/fastats/allergies.htm). We often don’t realize it, but our waiting rooms are usually filled with allergy patients. Many of them self-treat, while others—who have primary ocular signs and symptoms—are suboptimally managed with systemic anti-allergy medications.
Contact lens wearers often suffer the most; many of the over-the-counter (OTC) medications that they turn to can cause dry eye, which directly impacts lens comfort. Especially frustrating is that many of these patients fail to list allergy or allergy medications on their health intake forms. A surprising number of patients believe that OTC products are not medications, while others think the medications have “cured” their allergies.
More than 50% of contact lens wearers report suffering from allergies. A 2006 survey by the Asthma and Allergy Foundation of America (AAFA) found that 73% of lens wearers who reported allergy symptoms increased rewetting drop use, decreased lens wear, or simply removed their lenses in the middle of the day. Worse yet, when faced with allergy symptoms, 42% of patients completely stopped wearing lenses and switched back to spectacles without advising their eyecare practitioner or seeking help (www.medicalnewstoday.com/releases/47322.php). Considering the already high rate of contact lens dropout, an additional source of discomfort may be the final straw for some lens wearers.
To compound matters, allergy is on the rise throughout the United States (www.acaai.org/allergist/news/New/Pages/global-warming-allergy-sufferers.aspx). Global warming, worsening pollution, increasing urbanization, and myriad other factors (http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=190306) appear to be driving this trend. In some areas, allergy is approaching epidemic proportions, with allergy “seasons” lasting throughout most of the year. For all of these reasons, recognizing and proactively addressing allergy patients’ problems is an important requisite for a successful contact lens practice.
Allergy and Lens Wear
Allergy seems quite simple at first glance. A patient complains of itching, the diagnosis of ocular allergy seems obvious, you treat it with a topical antihistamine, and the problem is resolved. Only it’s not always that simple. When a contact lens is added to the mix, things can quickly get more complicated.
We sometimes forget that allergy is, in reality, a very specific form of inflammatory ocular surface disease. Contact lens wear itself can also prompt a significant inflammatory response. Whether allergy or inflammation comes first is a clinically important question, but one that may be difficult to answer. Is that red, itchy eye classic allergy, or is it a reaction to an off-brand solution that the patient purchased against advice? Is the lens heavily deposited because of chronic allergy, or has the patient worn the lens well past when it should have been discarded? Keep in mind that the eye has a limited range of response to a wide variety of insults. Solving more than one issue at a time can become extremely complicated.
From a holistic perspective, allergy upsets the delicate balance of the ocular surface environment, an environment already quite challenged by the presence of a contact lens. Consider this: most lenses approach an order of magnitude greater in thickness compared to the tear layer, which must stretch to accommodate the lens. Depending upon its diameter and fitting characteristics, the lens can divide the tear structure into isolated pre- and post-lens zones. In some cases, this can help block allergens from reaching sensitive ocular tissues, providing relief. In other cases, it can trap allergens against sensitive ocular tissues and exacerbate the eye’s response (Wolffsohn and Emberlin, 2011).
Allergy 101 for Lens Fitters
Pirquet first described allergy in 1906, explaining it as an exaggerated hypersensitivity response to substances in the environment that would normally be ordinary and innocuous. An immune response mediated by Immunoglobulin E (IgE), allergy represents a prototypical protective reaction to an allergen. Allergen-specific IgE, created during the sensitization phase of what is commonly referred to as the allergic cascade, populates mast cells—so named because of their mast-like structure—which then tethers the cells to critically important tissues. The mast cell is functionally a fortress armed with a variety of potent vasoactive compounds and reactive species, all of which can be released within an instant to counter an attack by a foreign invader.
Mast cells are specialized in both form and function. The mast cells on surface tissues such as the skin and conjunctiva are different from the mast cells within the respiratory system and internal organs. The reason is that different cell subtypes serve different functions and encounter different adversaries. These differences become important when understanding how mast cell-stabilizing compounds work. For example, stabilizing compounds that are effective on mast cells within the airways are generally ineffective on ocular surface mast cells.
Because of their important defensive role, mast cells contain large amounts of histamine and other potent chemicals that are released immediately upon contact with allergens. Mast cells also synthesize a variety of proinflammatory mediators, which can promote rapid mobilization of inflammatory cells through the vascular system. Early phase allergic response is the immediate localized response to an allergen. Late phase represents a systemic follow up that ensures the threat has been adequately neutralized. Because the eye is so critical to overall survival, the ocular response to allergens—tearing, for example—modulates the local response while limiting the more exuberant and potentially damaging late phase response.
While most of us recognize allergy as an immunological response initiated by an environmental trigger, the complex relation of allergy to the environment is often underestimated. For example, it is now well accepted that allergy originated as a natural humeral defense against parasitic infection (Yazdanbakhsh et al, 2002). This suggests that today’s allergy sufferers are the genetic heirs of those who survived parasitic epidemics eons ago.
The role of the environment in manifesting allergic tendency remains a hot topic. We increasingly recognize that allergy is more of an urban disease than a rural one. We also know that allergy varies with age and socioeconomic status (www.cdc.gov/nchs/data/databriefs/db121.htm). Younger and higher-income patients are more likely to be affected. Explanations for this include what allergists call “the hygiene hypothesis,” which states that greater exposure to pathogens during childhood decreases the potential for allergy. It should be noted that the demographic for allergy and contact lens wear overlap.
Clinical Allergy Management
Diagnosis is the first step in managing allergy patients. Although that seems to go without saying, it can be more difficult than you might imagine, especially considering how common allergy is.
First, acute allergy (Figure 1) is rarely encountered during an examination. Virtually all eyecare offices are air conditioned and filtered, shielding patients from environmental allergens that might torment them while outdoors or in other environments. Also, as mentioned before, with the broad array of OTC allergy treatment options, many patients self-treat. A surprising number of these patients perceive themselves as being allergy-free. A third issue is that many patients—even those who have significant ocular allergies—seek treatment from primary care physicians or allergists. Oddly, some eyecare providers follow a “don’t tell, don’t ask” philosophy, avoiding any discussion of allergy and leaving many patients who suffer from eye-specific allergy to be treated elsewhere.
Figure 1. Very inflamed eye with papillary response typical of an acute ocular allergic reaction.
Once a diagnosis is made, first-line treatment ideally consists of environmental management, which is much easier said than done except perhaps indoors. Pharmaceutical agents are the next and most common mode of allergy management for all patients.
Seasonal allergic conjunctivitis (SAC) is the most common form of ocular allergy encountered in eyecare offices. It typically presents as an acute response to an environmental allergen and produces the classic red, itchy, watery eyes (Figure 2). Although SAC is primarily a disease of the outdoors, patients can track allergens inside on their clothes and in their hair, contaminating indoor areas. Allergens can also enter through normal ventilation routes.
Figure 2. Classic injection and copious tearing from acute seasonal allergic conjunctivitis.
Perennial allergic conjunctivitis (PAC) occurs indoors throughout the year. PAC is typically milder and may be mitigated by environmental controls such as HEPA filters, removal of carpets, and dust-mite-proof linens.
Medical management of contact lens-wearing allergy sufferers should be initiated before lens fitting and continued throughout allergy season (Bielory, 2008). The typical and most effective treatment for ocular allergy is a topical antihistamine-mast cell stabilizer drop. Drugs in this class can be divided by dosing regimen. Optivar (azelastine hydrochloride 0.05%, Meda Pharmaceuticals), Alaway (ketotifen 0.025%, Bausch + Lomb [B+L]), Zaditor (ketotifen 0.025%, Novartis), Elestat (epinastine 0.05%, Allergan), Bepreve (bepotastine 1.5%, B+L), and Patanol (olopatadine 0.1%, Alcon) have b.i.d. dosing. Pataday (olopatadine 0.2%, Alcon) and Lastacaft (alcaftadine 0.25%, Allergan) are indicated for once-daily use and are generally preferred for contact lens wearers because of their added convenience and extended effectiveness.
Older antihistamines such as Livostin 0.05% (levocabastine, Novartis), which is still available outside of the United States, and Emadine (emadastine 0.05%, Alcon), as well as a number of topical mast cell stabilizers, are rarely used for primary treatment of allergy. Older mast cell stabilizers have limited effectiveness for treating SAC and PAC. In addition, q.i.d. dosing makes these older agents impractical for lens wearers.
Contact lens practitioners should be aware that most oral anti-allergy medications cause drying, which can complicate contact lens wear and actually exacerbate allergy. Topical medications deliver high concentrations of medication to the eye and have the lowest potential for side effects. Topical allergy medications are contraindicated while contact lenses are worn; however, some clinicians ignore this warning and risk possible preservative toxicity.
Contact Lens Issues in Allergic Patients
The past few years have seen tremendous advances in our understanding of the ocular environment and the importance of a stable tear film. Awareness of the impact of contact lenses on the ocular environment has also grown.
Most clinicians recognize that ocular allergy and dry eye frequently coexist (Hom et al, 2012; Gomes et al, 2013). In fact, dry eye often worsens allergy by concentrating allergens within the tears and by adding to the inflammatory load.
Meibomian gland dysfunction (MGD) is now recognized as a leading cause and a key contributor to dry eye through tear evaporation due to lipid deficiency (Lemp et al, 2012). The lack of a coherent lipid layer can worsen both dry eye and allergy. Therefore, treating MGD is strongly advised for all contact lens wearers. Anything that improves tear stability and volume will help minimize the allergic response by increasing allergen dilution and promoting more rapid tear clearance. The barrier created by a stable tear film may also help reduce potential allergen effect on the ocular surface.
For patients who suffer from allergy, frequent lens replacement is generally preferred, with single-use daily disposable lenses being ideal. Studies have demonstrated that daily disposable lenses provide greater comfort and reduce symptoms for allergy sufferers (Wolffson et al, 2010; Wolffson and Emberlin, 2011). They are also approved by the U.S. Food and Drug Administration for reducing symptoms of SAC. Advanced daily disposable lenses that release tear stabilizing and moisturizing agents appear more effective in reducing typical signs of ocular allergy compared to less advanced single-use lenses (Wolffson et al, 2011).
Astute contact lens fitters must be capable managers of ocular allergy simply because of the sheer number of patients impacted by allergy. Not many situations that we encounter clinically provide as much immediate gratification as successfully managing allergy in a contact lens wearer. CLS
For references, please visit www.clspectrum.com/references.asp and click on document #220.
Dr. Epstein co-founded Phoenix Eye Care PLLC and The Dry Eye Center of Arizona PLLC. He heads the practice’s Dry Eye - Ocular Surface Disease Center and serves as its director of Clinical Research. He is also a clinical adjunct associate professor at the Midwestern University, Arizona College of Optometry. He is a consultant or advisor to Alcon, EyeEco, Nicox, and TearScience, and has received research funding from CooperVision.