What is the difference between Pataday and Patanol?

Pataday and Patanol are both eye drops containing olopatadine as the active ingredient. Pataday contains a higher concentration of olopatadine (0.2 percent) versus Patanol (0.1 percent). Both products treat allergy eye symptoms, but because Pataday is more concentrated, it needs to be administered only once a day for full effectiveness.