Pataday® Once Daily Relief (0.2% olopatadine) is the first once daily eye allergy itch relief drop available without a prescription. A single drop of Pataday® Once Daily Relief works directly on the cells that make eyes itch. It’s fast relief that lasts all day. Itchy Eyes? Meet the Invisible Enemies. Did you know there are thousands of allergens in every cubic yard of air? Pollen, ragweed, and grass are the triggers we might think of first. But you don't have to set foot outdoors to have your day ruined by itchy allergy eyes. Pet dander and animal hair are among the most common indoor allergens. That's why there's Pataday®. Pataday® is made to relieve the itch caused by these every day culprits—both indoor and out. Pataday® works two ways. It goes to work on mast cells in the eye. (Mast cells house the histamines that make your eyes itch.) Pataday® stabilizes the mast cells, preventing them from releasing histamines. Pataday® also blocks histamines that have already been released from attaching to the histamine (H1) receptors in the eye, breaking the chain of allergic reaction. Less histamines means less allergy eye itch. Formerly prescribed as Pataday®, one drop of Pataday® Once Daily Relief (0.2% olopatadine) works fast and provides all day eye allergy itch relief. It can be used once a day for relief that lasts all day. HSA/FSA EligibleRestrictions apply; contact your insurance provider about plan allowances and requirements.