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18 EW NEWS & OPINION April 2013 Pharmaceutical focus Corralling ocular allergy by Maxine Lipner EyeWorld Senior Contributing Writer Medicines to help practitioners take the reins F or many visiting ophthalmologists' offices, allergy is a fact of life. Almost 15% of the worldwide population has ocular allergy, according to Vincent P. de Luise, MD, assistant clinical professor of ophthalmology, Yale University School of Medicine, New Haven, Conn. Available medicines for allergic conjunctivitis run the gamut from overthe-counter remedies to mast cell stabilizer antihistamine combinations, as well as steroids and beyond. "About one in seven people has some type of eye allergy," Dr. de Luise said. These fall into five broad categories—seasonal allergic conjunctivitis (SAC), perennial allergic conjunctivitis (PAC), vernal keratoconjunctivitis (VKC), atopic keratoconjunctivitis (AKC), and giant papillary conjunctivitis (GPC). Understanding allergy Most ophthalmologists, Dr. de Luise noted, will come across patients with SAC in their practices. One important clinical pearl is to remember that the hallmark symptom of allergy is itching. "If you don't obtain the symptom of an itchy eye, you can't make a diagnosis of ocular allergy," Dr. de Luise said. At its core, SAC is a type 1 GellCoombs hypersensitivity reaction. "It's mediated largely by the release of immunoglobulin E (IgE), and it involves mast cells that release histamine," Dr. de Luise explained. Besides histamine release, there Seasonal allergic conjunctivitis involves itch and can sometimes be marked by redness, chemosis, eyelid swelling, and tearing. Eye with papillary vernal conjunctivitis (note giant papillae) is also the discharge of other inflammatory mediators such as prostaglandin D2, leukotrienes, and tryptase, Dr. de Luise noted. "The conjunctiva predominantly contains H1 receptors, as well as receptors for prostaglandin D2," he said. "Itching is mediated largely by H1 receptors." Two other ocular signs, redness and hyperemia, are largely mediated by H2 receptors. H3 and H4 receptors also mediate histamine release and the itch response. Perennial allergic conjunctivitis (PAC) usually presents with milder signs and symptoms than SAC. "It's a year-round condition and is usually triggered by animal dander or the feces of dust mites," Dr. de Luise said. "About 90% of all ocular allergies are either SAC or PAC." windows closed if they're in an area where there are a lot of danders and keeping their air ducts clean," he said. Also, he encourages patients to first try simple things, such as the use of cold compresses and non-preserved artificial tears. Using cold compresses immediately reduces the histamine response. Meanwhile, having the patient use non-preserved artificial tears flushes out allergens without taxing the ocular surface. These strategies, however, are just palliative. "Non-preserved tears and cold compresses are not solving the underlying problem of the allergic response—they're just making the patient more comfortable, which is important, but doesn't solve the problem," Dr. de Luise said. Pure antihistamine drop such as levocabastine and emedastine are rapid actors in alleviating itch, however, Dr. de Luise usually recommends avoiding them since they alone can't solve the long-term problem of stabilizing the mast cells and usually require more frequent Treatment tree In treating these allergic conjunctivitis patients, Dr. de Luise suggested a stepwise approach, beginning with educating patients about avoiding allergens. "You should start by recommending that patients modify their environment by keeping their Source (all): Vincent P. de Luise, MD Minimally continued from page 17 places the iStent in the nasal inferior quadrant. "I don't really think it matters whether you use a right or a left stent. I would favor using the stent that is most ergonomically comfortable, whether it's a left or a right. The iStent is 'bidirectional,' so it shouldn't matter as long as it is well positioned," Dr. Samuelson told EyeWorld in an email after the seminar. Dr. Samuelson added he uses straight topical anesthesia, while Dr. Brown prefers retrobulbar for the iStent "because I'm still in the learning mode on it, but will probably move to topical when I'm more comfortable." Dr. Rhee uses a block or intraocular lidocaine for the Trabectome. "The ability to achieve more titratable glaucoma therapy is promising," Dr. Vold said. "Further, these devices allow comprehensive cataract surgeons to expand their practice into surgical glaucoma." EW Editors' note: This web seminar was sponsored by the ASCRS Glaucoma Clinical Committee, supported in part by Alcon (Fort Worth, Texas). Dr. Brown has financial interests with Ivantis and Transcend Medical. Dr. Samuelson has financial interests with Allergan (Irvine, Calif.), Glaukos, and Ivantis. Dr. Vold has financial interests with AqueSys, Glaukos, iScience Interventional (Menlo Park, Calif.), Ivantis, NeoMedix, SOLX (Waltham Mass.), and Transcend Medical. Dr. Rhee has financial interests with AqueSys. Contact information Brown: reaymary@comcast.net Rhee: dougrhee@aol.com Samuelson: twsamuelson@mneye.com Vold: svold@cox.net dosing. Likewise, although mast cell stabilizing agents can improve the problem over the long haul, they don't work quickly since histamines have already been released by the time the ocular allergy patient arrives in the office. "The ideal treatment of both seasonal allergic conjunctivitis and perennial allergic conjunctivitis would be a combined antihistamine mast cell stabilizer," Dr. de Luise said. "The advantage is rapid action from the antihistamine part and the long-term benefits from the mast cell stabilization part." The choices here include Patanol (0.1% olopatadine, Alcon, Fort Worth, Texas), Lastacaft (alcaftadine ophthalmic solution, Allergan, Irvine, Calif.), Bepreve (bepotastine besilate ophthalmic solution 1.5%, Bausch + Lomb, Rochester, N.Y.), Zaditor (ketotifen fumarate ophthalmic solution, Novartis, Basel, Switzerland), Elestat (epinastine hydrochloride ophthalmic solution, Allergan), and Optivar (azelastine, Meda Pharmaceuticals, Somerset, N.J.). While Patanol was the original combination agent, Dr. de Luise pointed out that it needs to be dosed twice daily for maximum efficacy. "Now there is Pataday [0.2% olapatadine, Alcon], which is a longer acting antihistamine plus mast cell stabilizer, with once-a-day dosing, which is more convenient and improves compliance," Dr. de Luise said. Likewise, Lastacaft can be dosed once a day and also has action against H1, H2, and H4 receptors. "It's dosed once a day and also seems to reduce eosinophilic migration," he said. "It's conceivable that alcaftadine is even more potent and has more benefits than the other agents, but I don't think that has been proven in a clinical trial." All of the other combination agents, he pointed out, have to be dosed twice a day or more. For those patients who cannot be controlled by these medications alone, and in whom there is no other contraindication, Dr. de Luise would recommend a short course of topical steroids, but that's reserved for unusually severe cases. "It's very rare that you can't control these people with SAC," he said. "If you're continued on page 20