The present invention provides an eye drop formulation in the form of a solution, comprising (2R,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(1H-imidazol-2-ylmethyl)amino]-3-hydroxy-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran or a pharmaceutically acceptable salt thereof; propylene glycol as a stabilizing agent; and a pH controlling agent in an aqueous medium, wherein the eye drop formulation has a pH ranging from 4.0 to 5.0. The eye drop formulation of the present invention can contain (2R,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(1H-imidazol-2-ylmethyl)amino]-3-hydroxy-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran or a pharmaceutically acceptable salt thereof in a high concentration; and has an excellent stability. In addition, the pharmaceutical product for preventing or treating macular degeneration according to the present invention can be stored for extended periods.