Pretreat eye allergies for better surgical results

Allergic rhinitis affects about 30% to 40% of the U.S. population and of these individuals, 50 million also are plagued with allergic conjunctivitis, pointed out Dr. Mah, assistant professor of ophthalmology, University of Pittsburgh Medicine, Eye & Ear Institute, Pittsburgh. Since allergy sufferers are typically younger patients, there is the potential to see more of these patients in a refractive surgical clinic, making it critical to assess the location and severity of allergy symptoms.

Various mast cell stabilizers are available, such as nedocromil sodium (Alocril, Allergan), permirolast potassium (Alamast, Santen), and lodoxamide tromethamine (Alomide, Alcon Laboratories), although they require long-term usage before surgery.

Other topical mast cell stabilizers are quicker acting in onset due to antihistamine properties, including azelastine HCl (Optivar, MedPointe Healthcare), ketotifen fumarate (Zaditor, Novartis Ophthalmics), epinastine HCl (Elestat, Allergan), and olopatadine HCl (Patanol, Alcon). In his refractive surgery center, Dr. Mah has used all of the available antihistamine/mast cell stabilizers and he has found olopatadine HCl to be preferred by most patients, he said.

"The key issue is to identify these patients who have allergic symptoms, start treating them with a topical antihistamine, and eliminate the systemic agent," which can induce or exacerbate dry eye symptoms, Dr. Mah noted.

Those at risk

Patients with atopic dermatitis are prone to severe dry eye and at high risk for severe ocular herpes simplex virus infections. In fact, atopic dermatitis has also been linked to retinal detachments, cataracts, and keratoconus.

In a 2003 study from the University of California, Irvine, researchers proposed a "cascade hypothesis" as the cause of keratoconus in these atopic individuals. In these eyes, abnormal or defective enzymes lead to oxidative damage. This, in turn, triggers apoptosis, altered signaling pathways, increased enzyme activities, and fibrosis. In patients with keratoconus or forme fruste keratoconic-type topography, Dr. Mah suggests treating patients with artificial tears and allergy medications. Even individuals without a history of allergy or asthma are prescribed these therapies, he said.

"We know it makes sense to reduce any type of eye rubbing and continued oxidative damage in the patients that admit rubbing of their eyes. We are assuming that prophylactically, if we treat patients that are at risk, we may be able to prevent progression even in those patients that do not have a history of atopy or eye rubbing," he said.