  It is shown that the geometrical optics limit of the Maxwell equations for
certain nonlinear media with slow variation along one axis and particular
dependence of dielectric constant on the frequency and fields gives rise to the
dispersionless Veselov-Novikov equation for refractive index. It is
demonstrated that the last one is amenable to the quasiclassical DBAR-dressing
method. A connection is noted between geometrical optics phenomena under
consideration and quasiconformal mappings on the plane.
