Epiretinal implants are placed on top of the retinal surface, above the nerve fiber layer, directly stimulating ganglion cells and bypassing all other retinal layers. Array of electrodes is stabilized on the retina using micro tacks which penetrate into the sclera. Typically, external video camera onto eyeglasses acquires images and transmits processed video information to the stimulating electrodes via wireless telemetry. An external transmitter is also required to provide power to the implant via radio-frequency induction coils or infrared lasers. The real-time image processing involves reducing the resolution, enhancing contrast, detecting the edges in the image and converting it into a spatio-temporal pattern of stimulation delivered to the electrode array on the retina. The majority of electronics can be incorporated into the associated external components, allowing for a smaller implant and simpler upgrades without additional surgery. The external electronics provides full control over the image processing for each patient.