1. A method of measurement, comprising: obtaining a corneal anterior surface map from a first imaging method; obtaining an epithelial thickness map from a second imaging method; combining the corneal anterior surface map and the epithelial thickness map to obtain a stromal elevation map and a topographic map of a stromal corneal curvature; and displaying the topographic map, wherein the combining the corneal anterior surface map and the epithelial thickness map includes calculating the difference between the corneal anterior surface map and the epithelial thickness map.