Allergies and Dry Eye in Contact Lens Wearers
BY KELLY K. NICHOLS, OD, MPH, PHD
With allergy season starting (or ending) in some places and in full swing in others, it's timely to consider the close relationship among seasonal allergies, lens-related dry eye, discomfort and ultimately, a concurrent decrease in comfortable wearing time.
In general, it makes clinical sense that a patient who has seasonal allergies may experience contact lens discomfort during a seasonal flare-up. The allergic immune response creates a myriad of additional tear proteins, inflammatory mediators and changes to the local vasculature on the ocular surface. All of this results in increased mucus and protein deposition on the lens surface, and a potential decrease in tear film stability.
Studying Ocular Allergy
Unfortunately, it's a challenge (literally) to study ocular allergy. One type of study is a conjunctival antigen challenge (CAC), in which researchers apply an allergenic source topically to the eye and measure common indicators of allergic response (redness, tearing, conjunctival edema). A pharmaceutical agent is generally applied before or after the challenge. In such studies, researchers can select "allergy responder" patients, thereby normalizing the types of patients enrolled. A pitfall of CAC studies is they're not very real world.
A second type of allergy study is an environmental challenge, in which people who have ocular allergies are randomized to receive medication or placebo drops while performing their regular activities. In addition to requiring large numbers of patients, the major problem with such studies is the unpredictability of Mother Nature. Months of planning and organizing may go into a study only to have it occur during a period of record-low pollen levels.
Contact Lenses and Allergy
Counsel patients on lens hygiene, cleaning and frequent disposal during allergy season. Clean lenses with minimal deposition provide the most comfortable lens environment and reduce the transient blur often reported by allergy sufferers. Hayes et al (2003) and others have recommended daily disposable lenses or more frequent replacement of lenses.
The hallmark symptom of ocular allergy is itch, but contact lens patients often report that they need to rub their eyes during lens wear and especially after lens removal. Consider prescribing topical antihistamine/mast cell stabilizers b.i.d. (pre- and post- lens wear). Advise patients to not use topical anti-allergy drops while the lenses are in place.
Allergy Medication Side Effects
Patients who have seasonal allergies may take oral antihistamines and decongestants that have drying effects. Anticipate that contact lens patients who have dry eye may have symptoms flare-up during allergy season and that allergy sufferers may experience dry eye. Consider additional lubrication and medications that may address both conditions, such as low-dose topical steroids or topical cyclosporine.
Manage Patients Proactively
For patients who suffer from allergy-related symptoms, monitor their allergy status. If a contact lens patient comes in for a routine exam when it's not allergy season, ask him about any seasonal allergy symptoms and encourage him to return during the troublesome time for an allergy-related check-up. As Lemp (2003) stated, "With careful attention to recognizing the patient with ocular allergy, regular monitoring, and patient compliance to lens care, successful contact lens wear can be achieved in most patients with ocular allergy."
For references, please visit www.clspectrum.com/references.asp and click on document #125.
Dr. Nichols is an associate professor at The Ohio State University College of Optometry in the area of dry eye research.