Apparatus for ophthalmic electrophysiological testing, the apparatus comprising: an EER stimulator for providing an electrical stimulus to an eye so as to evoke an electrophysiological response, wherein the EER stimulator comprises a power source； an amplifier for receiving the electrophysiological response and measuring that response, wherein the amplifier is integrated with the EER stimulator； and at least one switch disposed between the power source and the amplifier for isolating the power source from the amplifier when the electrical stimulus is delivered to the eye.
