(EN)"Universal improvement" of vision is achieved by effectively changing the shape of the anterior refracting surface of the cornea to an ideal "turtleback" shape, on which is imposed the necessary curvature adjustment to achieve correction of distance vision. In accordance with one embodiment, the cornea is actually formed to the turtleback shape through corneal surgery, preferably laser ablation surgery. In accordance with a second embodiment, a contact lens with the desired distance corrected ideal turtleback shape on its anterior surface is positioned over the cornea.