The purpose of this study is to evaluate the effectiveness and safety of Olopatadine Hydrochloride (HCl) ophthalmic solution 0.1% versus Epinastine HCl ophthalmic solution, 0.05% in a population of healthy, adult Japanese patients (20 years of age or older) with a history of allergic conjunctivitis to Japanese Cedar Pollen. Patients will be randomly assigned to receive Olopatadine HCl ophthalmic solution, 0.1% in one eye and Epinastine HCl ophthalmic solution, 0.05% in the fellow eye, after which a conjunctival allergy challenge (CAC) with Japanese cedar pollen will be performed.