The object the present work is to present a model for a retinal prosthesis. The translation of an algorithm on the standard technology of silicon sets a trade off between accurate of model and feasibility to implementation. That is, a high accurately of the model, normally results in more complexity, and therefore minus feasibly its implementation in hardware. To develop the model was necessary to review the receptive field concept, its classification and retinal architecture. The model consists in to reproduce the signal in a ganglion cell. This model has the advantage that is very simple with a high feasibly to implement on standard technology silicon. The mathematical representation comprises sustained and transient response which is the classification of the receptive fields. A second contribution of this work is the interpretation of the response of ganglion cell which will be analyzed along the developmental of this work. Simulations results are presented using the mathematical representation.