trailing blunt end 54 of the dissecting ring the method of implanting an adjusting ring 47 within the cornea of the eye is as follows first a determination is made by taking optical measurements of the eye as to what shape the cornea should have in order for that eye to operate in an optically correct manner fig1 shows a target image comprised of indicia 81 this target grid 81 may be made by reflecting light from placido rings from a standard spherical surface the same size as the eye in question and at a fixed distance an image is made of this 34 correct 34 topographic map of the eye referred to herein as a target or target image the target indicia is in the form of vertical lines or grids 81 as shown in fig1 which of course may be drawn in other radial meridians as well as the horizontal meridian as shown the spacings between the grids 81 represents a topographic survey of an eye having a corrected curvature as pertains to the specific eye in question a dissecting ring 51 is next placed in the groove 77 on the concave surface 76 of the rotatable holding member 72 the blunt end 54 of ring 51 is contacted against the pin 78 extending outwardly from the groove the magnetic attraction between the magnetic member 72 and steel ring 51 holds.