Apparatus for evoking and sensing ophthalmic physiological signals in an eye, the apparatus comprising: an elongated tubular light pipe having a longitudinal axis, a distal end and a proximal end, the distal end terminating in a spheroid recess； an active electrode having a distal end and a proximal end, the active electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the active electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe； and a reference electrode having a distal end and a proximal end, the reference electrode being mounted to the elongated tubular light pipe and extending proximally along the elongated tubular light pipe so that the distal end of the reference electrode terminates at the spheroid recess at the distal end of the elongated tubular light pipe； wherein the distal end of the active electrode is located closer to the longitudinal axis of the elongated tubular light pipe than the distal end of the reference electrode.
