This paper presents 288-pixel retinal prosthesis chip in 0.18 um CMOS process. Proposed light-to-stimulus duration converter and biphasic stimulator achieve a wide range of retinal stimulation proportional to the incident light intensity at low supply voltages of 1V. The implemented chip demonstrates 18.9x-continuosly-varied stimulus duration control at a 6 Hz stimulation rate, and achieves the state-of-the art low power consumption of 4.49 nW/pixel.