Optical coherence tomography ("OCT") corneal mapping apparatus includes an OCT apparatus having a rotating helical mirror for altering a reference beam path in the OCT apparatus; a raster scanner for raster scanning sampling optical output from the OCT apparatus; a curved mirror for transferring the sampling optical output from the raster scanner to an eye and for transferring sampling optical output reflected from the eye back to the OCT apparatus through the raster scanner; and an analyzer, coupled to the raster scanner, the rotating helical mirror, and reference and sampling interaction output from the OCT apparatus. The analyzer causes the raster scanner to scan the sampling optical output to points in a raster; causes the rotating mirror to alter the length of the reference beam path over a predetermined amount at each of the points in the raster; and provides the corneal mapping from the reference and sampling interaction output at the points in the raster.