Olopatadine in Seasonal Allergic Conjunctivitis: Efficacy, Ocular Surface Safety, and Practical Considerations for Preservative-Free Multidose Therapy

Background

Seasonal allergic conjunctivitis (SAC) is the most prevalent form of ocular allergy, characterized by recurrent episodes of IgE-mediated conjunctival inflammation triggered by seasonal aeroallergens (pollens). Its clinical course typically spans 4–12 weeks for individual pollen taxa and may extend considerably longer in polyallergic patients. Olopatadine hydrochloride ophthalmic solution, a selective H1-receptor antagonist with mast cell-stabilizing properties, is one of the most extensively studied topical antihistamines for SAC and is highly ranked in comparative evidence networks. Two clinically relevant aspects have received insufficient attention: the impact of benzalkonium chloride (BAK), a preservative, on the conjunctival surface, and the implications of bottle size for treatment adherence during SAC’s prolonged symptomatic periods.