A method and composition for hyperthermally treating cells in the eye with simultaneous imaging. The heat (temperature) production inside the eye (target) tissue is imaged. The desired temperature is achieved using a laser and photoacoustic imaging technique. Hyperthermia treatment of tissue in a target site applies a heat source to kill cells without protein denaturation. The method introduces an encapsulated dye that is released at a selected temperature in the target site to indicate that a threshold temperature has been reached to hyperthermally treat the tissue. In one embodiment, the composition releases the dye at a temperature of 42° C. to 50° C., and preferably about 45° C. to 49° C. The composition which can be a liposome composition encapsulating the dye can be introduced to the bloodstream of the patient to flow through the target site.