1. A system for registering and tracking the position of a person's eye, in particular for refractive ophthalmic surgery, comprising: a camera system for taking images of the person's eye; storage means connected to the camera system for storing at least one eye image as a reference eye image; an image processing system connected to the storage means and/or the camera system for comparing a momentary eye image with the reference eye image and for outputting a signal representing a change of eye position between the reference eye image and the momentary eye image, wherein the system is designed such that eye images containing at least the iris and the pupil of the eye are made at a first wavelength of light and that eye images containing scleral blood vessels are made at a different second wavelength of light.