Finding the Right Treatment for a Widespread Problem
BY WILLIAM L. MILLER, OD, PHD, FAAO
Nearly 54 percent of patients were sensitive to at least one of 10 allergens tested according to the National Health and Nutrition Examination Surveys III report (Arbes et al, 2005). Another study (Smith et al, 2005) using a Visual Functioning Questionnaire (VFQ-25) reported that patients suffering from allergic conjunctivitis (AC) had significantly lower scores in overall vision, ocular pain and mental health. From clinical experience and other studies, it's evident AC is a common problem.
Seasonal (SAC) and perennial allergic conjunctivitis (PAC) make up nearly 98 percent of AC. SAC is a response to tree pollen, grass, plants or mold. PAC results from animal dander, dust mites and feathers.
Using animal and human models, our understanding of AC is progressing. Reasons for mast cell degranulation and histamine release, as well as similarities between AC subtypes, are clearer. Inflammatory markers like TH2-associated ß cytokines and chemokines have been identified with SAC. Ongoing study may advance therapies targeting the allergic-mediated inflammatory cycle further upstream than current medications.
AC Treatment Options
The first line of treatment is cold compresses and tear supplements (non-preserved) that provide symptomatic relief and allergen tear dilution. Additional therapy for those suffering from episodic, mild forms of AC may include over-the-counter topical drops. Some may avoid these because of rebound hyperemia, mydriasis and alpha-adrenergic sensitivity in patients who have cardiovascular problems. However, they represent satisfactory treatment for healthy patients who have occasional, mild forms of SAC and PAC. Patients use these drops as needed and must instill them before and after contact lens wear. That's also important to note for other AC medications.
Other treatments include formulations that contain either an antihistamine or mast cell stabilizer. Antihistamines such as Emadine (Alcon) and Livostin (Novartis) provide quick relief for acute situations. Both are instilled qid. Mast cell stabilizers such as pemirolast (Alamast, Vistakon), nedocromil (Alocril, Allergan) and cromolyn sodium (Crolom, Bausch & Lomb) provide long-term relief with additional loading in the initial treatment window. The most common treatment for SAC and PAC includes twice-a-day combination drops containing an antihistamine and mast cell stabilizer. Drugs in this class include epinastine HCI ophthalmic solution 0.05% (Elestat, Allergan, Inspire) azelastine hydrochloride ophthalmic solution 0.05% (Optivar, MedPoint Pharmaceuticals), olopatadine hydrochloride ophthalmic solution 0.1% (Patanol, Alcon) and ketotifen fumarate ophthalmic solution 0.025% (Zaditor, Novartis).
Many also use systemic anti-allergy medications that may exacerbate ocular symptoms by alter- ing tear film and potentiating any allergens on the ocular surface.
At least one NSAID (Acular, Allergan) is FDA approved for AC, although its efficacy for periods more than one week is unknown. Short-term pulse steroid application is necessary in severe forms of AC but is more applicable in other chronic forms of AC.
The Right Therapy
A sophisticated approach to AC includes a complete history with a summary of AC peak periods and magnitude (mild, moderate or severe). Determining previous use of anti-AC medication or treatment may help you tailor the eventual therapy to maximize results and make the patient more comfortable.
Dr. Miller is on the faculty at the University of Houston College of Optometry. He is a member of the American Optometric Association and serves on its Journal Review Board. You can reach him at email@example.com.