An ophthalmic solution containing diquafosol to which a chelating agent is added, wherein the formation of an insoluble precipitate during storage and a lowering in filtration performance in a production process (a filtration/sterilization process), said insoluble precipitate formation and said lowering in filtration performance being observed in conventional ophthalmic solutions containing diquafosol, are inhibited. It is also confirmed that the ophthalmic solution containing diquafosol to which a chelating agent is added shows an improved ability to retain the effect during storage. Therefore, the present invention provides an ophthalmic solution containing diquafosol, said ophthalmic solution having stable physicochemical properties in the course of production, distribution and storage by a patient, in particular, enabling efficient filtration/sterilization in the production process, and, moreover, having an excellent ability to retain the effect during storage. Also, the present invention provides a method for preventing the formation of an insoluble precipitate from an aqueous ophthalmic solution containing diquafosol or a salt thereof, said method comprising adding a chelating agent to the aqueous ophthalmic solution.
