Retinal prosthesis represents the best near-term hope for individuals with chronic blinding disease of the outer retina. However the small number of stimulating electrodes produces a poor, low resolution image. We propose a new preprocessing method for epi-retinal implants and validate it through a novel simulation of the implanted blind perception. Twenty-one normally sighted, untrained subjects performed a face recognition test. Three different electrodes grids were simulated: rectangular, hexagonal and log-polar. The results show that the proposed pre-processing method has a good and statistically significant performance improvement.