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Background: Visual prosthesis based on penetrating optic nerve (ON) electrical stimulation is a promising approach to restore vision for blindness with severe ocular fundus disease.However surgical pathway of ON prosthesis chronically implantation and optimal ON electrical stimulating strategies still need further investigation.Methodology/Results: We did ON exposure surgery on an adult rhesus monkey under deep anaesthesia.Burke-Kronlein incision was performed from the left external canthus toward the base of ear helix and ~12mm lateral orbit rim was cut to fully expose ON right behind the globe of the eye.Then we conducted ON fenestration to remove dura and implanted a penetrative stimulating microelectrode array into the ON.Normal visual evoked potentials (VEP) to flash stimulus through the surgical eye could be obtained one week after the surgery.In-vivo electro-physiological experiments in rabbits and cats were done to study the cortical electrically evoked potentials (EEP) in response to ON stimulation with different waveforms of biphasic charge-balanced pulse.Visual topography of the ON stimulating and EEP recording sites were mapped using reverse correlation analysis.We found EEP amplitudes were significantly larger in response to asymetric electrical stimuli than symetric stimuli and EEP peak positions were topographically matched with the ON electrical stimulating sites.Psychophysical studies were designed to examine the effect of phosphene luminance, flicker rate, and eccentricity on the ability to estimate simulated phosphene sizes using tactile perception and investigate the ability of normally sighted subjects to recognize images, Chinese characters and reading performance after altering stimulated phosphene maps.The results indicated that the reported phosphene size linearly increased as visual stimulus size increased.Judgment was significantly affected by stimulus luminance and eccentricity but not by flicker rates.The altering stimulated phosphene map has significant impact on pixelated images, Chinese characters recognition and paragraph reading performance.Conclusions: ON electrical stimulation with penetrative electrodes is expected to restore pattern vision in large visual field.