1. A method for aligning a first and a second image of an eye comprising the steps of: determining a limbus location on a first eye image and a second eye image; aligning the limbus location of the first and the second eye images in two dimensions; determining a location of a second eye feature on the first and the second eye image; relatively rotating one of the first and the second eye image; performing a correlation on the first and the second eye image at a plurality of relative rotational positions using the second eye feature location; and from the correlation, identifying an optimal first and second image alignment.