PROBLEM TO BE SOLVED: To provide an ophthalmic aqueous solution that contains PGF2α analogue and contains substantially no preservatives.SOLUTION: An ophthalmic aqueous solution comprises 0.0015%w/v tafluprost, 0.075-0.1%w/v polysorbate 80, 0.01-0.1%w/v disodium edetate, and optionally buffering agents and tonicity agents conventionally used in ophthalmic solutions, and contains benzalkonium chloride.SELECTED DRAWING: None【課題】PGF2α類縁体を含み、かつ実質的に保存剤を含まない点眼水溶液の提供。【解決手段】点眼水溶液は、0.0015%w/vのタフルプロストと、0.075~0.1%w/vのポリソルベート80と、0.01~0.1%w/vのエデト酸二ナトリウムと、必要に応じて、点眼液で常用されている緩衝剤及び等張化剤を含み、かつ、塩化ベンザルコニウムを含まない。【選択図】なし