Systems and methods for treating an ocular condition includes a heating chamber comprising a material expandable when heated and comprising a flow passage having an inlet and an outlet. A heating element is arranged and disposed to introduce heat in the heating chamber. A flexible diaphragm separates the heating chamber from the flow passage, and is moveable between a first position and a second position to change a volume of one of the pump chamber and flow passages in response to a temperature change in the heating chamber.