Accurate corneal power is important specifically when calculating intraocular lens (IOL) power. Different IOL power calculating formulas are available today using different corneal power. The more traditional formulas still use power values derived from sagittal power maps, but during the calculation process the formula corrects for the use of the assumed refractive index. Newer generation formulas and ray traced formulas are more advanced and incorporate Ks from power maps such as TNP and TCRP.
Furthermore in the case of toric IOL implants, as well as post-refractive patients, newer generation formulas generate better post-op outcomes. Better Ks, better formulas lead to better results.