The invention relates to ophthalmology and is used for treating keratoconus. The inventive method comprises forming one or more radiation areas of different shape, comprising concentric circles, arcs, parallel lines, cells, grids, spirals or other geometrical figures. In the other variant, the method comprises polarizing UV radiation and adjusting the depth of the UV radiation action by directing the UV radiation polarization plane at an angle of 1-180° to the plane of light polarization by the cornea, thereby using the effect of light polarization by the cornea. The device for treating keratoconus comprises, positioned on the optical axis common with an UV radiation source optical focusing elements and a diaphragm. The diaphragm is situated on the optical axis common with the UV radiation source and is made in the form of a mask with alternating transparent and shaded elements in the form of concentric circles, arcs, parallel lines, cells, grids, spirals or other geometrical figures. In the other variant, the device comprises, situated on the optical axis common with the UV radiation source, the optical focusing elements, the diaphragm and a polarisor.