A clear ophthalmic solution containing latanoprost having a concentration of 0.005% (W/V), 0.003 to 0.01% (W/V) benzalkonium chloride and at least one agent selected from the group consisting of glycerin, polyethylene glycol, propylene glycol and trehalose, wherein the agent is in a concentration to make the solution isotonic. A method of preventing white turbidity in an ophthalmic solution containing latanoprost having a concentration of 0.005% (W/V) and 0.003 to 0.01% (W/V) benzalkonium chloride, the method involving adding to the solution at least one agent selected from the group consisting of glycerin, polyethylene glycol, propylene glycol and trehalose, wherein the agent is in a concentration to make the solution isotonic.