Corneal topography analysis before and after single-segment Intacs placement. The preoperative topography (lower left) shows oblique steepening, and the postoperative topography (upper left) shows contraction of a steep cone after a single-segment Intacs was placed outside the cone. The difference map (subtraction of preoperative and postoperative topography) (right) shows flattening over the cone (blue) and steepening in the overly flat area (red). The apex of the cornea has moved more centrally.