Several experimental data about membrane dynamics and pharmacological sensitivities of optic nerve axons have been published. The present work summarizes these data and computer simulations have been used to develop a model of the mammalian optic nerve fibre. The ionic currents description were derived from existing membrane models and particularly from a model of the somatic retinal ganglion cell (RGC) impulse generation. However, original equations had to be modified to match experimental data, which suggests that in RGCs, axonal and somatic ion channel expression are different. The new model is consistent with recent experimental results about optic nerve axonal excitability.