Abstract: A method and system control the depth of corneal ablation during optical surgery by mapping the anterior and posterior surfaces of a patient's cornea to obtain full pachymetric topographical mapping of the patient's cornea. The patient's corneal pachymetric topographical mapping is used to identify a desirable corneal bed, and to guide a surgical laser in ablating a portion of the anterior surface of the patient's cornea to produce the desired corneal bed for appropriate vision correction.