A Study to Evaluate the Safety and Efficacy of the QLT Proprietary Olopatadine-PPDS in Subjects With Seasonal Allergic Conjunctivitis to Ragweed in an Environmental Exposure Chamber Model.

Inclusion Criteria: * History of allergic conjunctivitis to ragweed for at least one year * Positive skin prick test to ragweed pollen within 12 months prior to visit 1 * BCVA of at leat 20/400 Exclusion Criteria: * Structural lid abnormalities (ectropion, entropion) * Active lid disease ( ie moderate or severe blepharitis, meibomianitis) that requires medical treatment * Presence of follicular conjunctivitis, anterior uveitis or preauricular lymphadenopathy * History of ophthalmic abnormality, including a history of dry eye * Perennial allergic rhinoconjunctivitis having significant allergy to animal dander that cannot be avoided during the study period * History of chronic bacterial or viral ocular infection, such as herpes keratitis, and/or presence of active bacterial or viral ocular infection * presence of mucous discharge, excess lacrimation or burning as a symptoms of ocular disease * Currently on any chronic ocular topical medications * Use of topical or systemic ocular medications during the study period * History of complications, adverse events, trauma or disease in the nasolacrimal area * History of symptomatic epiphoria