The numerical model of refractive properties of the eye lens is given. Crystalline lens is presented in a form of hundreds ellipsoidal shells with rotational symmetry, having the constant refractive index inside every shell. The refractive index between the surfaces increases from the cortical shell to the inner one, according to the exponential dependency. To complete the model of the optical system of the eye, the cornea approximated by two ellipsoidal surfaces is added in front of the crystalline lens. Ray tracing procedure is applied to study the refraction of rays through such a system. By changing the refractive index profile, optical properties of given model are analyzed. Results of calculations are compared with experimental data.