We have investigated the magneto-optical response in the visible spectrum of thin-film ferromagnetic manganites. We observe a huge enhancement of the magnetorefractive effect (MRE) around the Curie temperature, which is linked to the colossal magnetoresistance. It is found that the unusually large MRE at visible frequencies is accompanied by an increase in the magnetic field of the optical conductivity. We argue that these remarkable phenomena are related to the field-induced suppression of Jahn-Teller dynamical charge localization.