A system for positioning an eye of a patient, for example, for laser ophthalmic surgery includes a reflectometer adapted to receive as input a reflected beam from an anterior surface of a cornea of an eye of a patient. The interferometer is calibratable to a desired position of the corneal anterior surface. A comparator is in signal communication with the interferometer and is adapted to calculate from the input a difference between an actual position and the desired position of the corneal anterior surface. A device is in signal communication with the comparator for moving the patient a distance in a direction for matching the actual position to the desired position of the corneal anterior surface.