An apparatus for delivering therapeutic agent to an eye comprises a body, a cannula, a hollow needle, an actuation assembly, and a detection/visualization system. The cannula extends distally from the body and is sized and configured to be insertable between a choroid and a sclera of a patient's eye. The actuation assembly is operable to actuate the needle relative to the cannula to thereby drive a distal portion of the needle along an exit axis. The cannula may be inserted through a sclerotomy incision and advanced through the choroid to deliver the therapeutic agent adjacent to the potential space between the neurosensory retina and the retinal pigment epithelium layer. The detection/visualization system is operable to detect or visualize penetration of the choroid of a patient's eye and provide feedback to the operator and/or automatic control of the apparatus based on penetration of the choroid.