As the winter temperatures finally start to rise, so to will the inevitable blossoms and buds marking the start of Spring. While these changes are a welcome respite from the cold, for many of us there is a bittersweet realization that seasonal allergies are coming as well.
If you don’t suffer from seasonal allergies, chances are you know at least a few people that do. In the United States, seasonal and perennial allergies affect 20% of the population, and 70% to 80% of these patients report that their allergies include red, itchy, watery eyes. 1,2
Cool compresses and avoidance of the offending allergen may suffice for mild, momentary symptoms, but they often aren’t enough or practical on a day-to-day basis. Topical relief for symptoms, however, can be very effective in relieving symptoms and restoring quality of life.
But which type of medication is the most effective? Answering this question requires an understanding of the allergic reaction in the first place. Like other allergies, allergic conjunctivitis (red, itchy eyes) is caused by a hypersensitivity reaction to something in the environment.
2 Exposure to these allergens triggers something in the body called mast cells to release histamine, among other things, that induce symptoms such as itching eyes and redness. A mast cell is like a piñata that you don’t want to open, with histamine being a very itchy type of candy. Additional symptoms include eyelid swelling and tearing. While these symptoms may mimic “pink eye” to some degree, the major difference involves the presence of itching. 3,4
A number of over-the-counter topical agents are available (such as naphazoline) – these drugs are effective at reducing redness but do very little to treat itchy eyes. 5
Having no effect on the mast cells responsible for releasing the agents that cause ocular allergy symptoms, these drugs often don’t work well enough to treat your symptoms. Another group of eye drops are called “mast cell stabilizers”. If our metaphorical piñata doesn’t open, histamine can’t be released which can prevent itching from occurring. These medications first became available for topical ophthalmic use in the 1980s.6,7
While these drugs help in reducing itchy eyes, they are relatively short-acting. To be effective they must be taken before exposure to known allergens. This strategy takes some planning and won’t be very effective for someone who is already experiencing symptoms.
A third group of drops, called antihistamines, work well for acute symptoms, especially itching. Some of the first eye drops on the market were relatively short-acting, and used to treat both redness and itchiness in the eyes.8,9 Some of these drops are still available today as non-prescription drops but they have been replaced in recent years by more effective antihistamines. A noteworthy aspect of antihistamine drops is that, unlike the pure mast cell stabilizers, these drugs are effective whenever someone experiences allergic symptoms.
A progression of antihistamines has occurred in recent years, including Asteline ®, Bepreve ®, Zaditor ® and Patanase ®. Each of these are “dual-action” antihistamines that also stabilize mast cells.10-13 Meaning, they not only prevent allergy symptoms from developing but also relieve any itching that still may occur. In addition to this dual-action effect (or perhaps because of it), these newer drugs all last longer than their predecessors. Most recently, two of them have been approved for once-daily dosing—a higher concentration formula (0.2%) of olopatadine hydrochloride, (Pataday, Alcon), and the newest ocular antihistamine, alcaftadine (Lastacaft, Allergan). 14,15
While not all patients get the appropriate relief from these medications, they are a recommended starting point in therapy given how safe they are, with limited side effects. Ultimately, knowing which drop or treatment method is best for you should be done by your eyecare professional. To take advantage of the most effective treatments for ocular allergies, time is of the essence. It is important to know your options before symptoms already are impacting your daily life. Don’t get stuck in the weeds, make an appointment to be examined today.
J. Mark Snyder, O.D.
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11. Greiner JV, Mundorf T, Dubiner H, et al. Efficacy and safety of ketotifen fumarate 0.025% in the conjunctival antigen challenge model of ocular allergic conjunctivitis. Am J Ophthalmol. 2003 Dec;136(6):1097-105.
12. Sharif NA, Xu SX, Miller ST, et al. Characterization of the ocular antiallergic and antihistaminic effects of olopatadine (AL-4943A), a novel drug for treating ocular allergic diseases. J Pharmacol Exp Ther. 1996 Sep;278(3):1252-61.
13. Macejko TT, Bergmann MT, Williams JI, et al. Multicenter clinical evaluation of bepotastine besilate ophthalmic solutions 1.0% and 1.5% to treat allergic conjunctivitis. Am J Ophthalmol. 2010 Jul;150(1):122-27.e5.
14. Abelson MB, Spangler DL, Epstein AB, et al. Efficacy of once-daily olopatadine 0.2% ophthalmic solution compared to twice-daily olopatadine 0.1% ophthalmic solution for the treatment of ocular itching induced by conjunctival allergen challenge. Curr Eye Res. 2007 Dec; 32(12):1017-22.
15. Torkildsen G, Shedden A. The safety and efficacy of alcaftadine 0.25% ophthalmic solution for the prevention of itching associated with allergic conjunctivitis. Curr Med Res Opin. 2011 Mar;27(3):623-31.