| abstract |
A system of defining a reference axis of a patient's eye in an external coordinate system, comprising: a light source for directing a light beam on a reflective surface associated with the patient's eye, an imaging system for recording an image of a limbus of the patient's eye and an image formed by a reflection of the light beam from a cornea of the patient's eye, and a processor operatively connected to the imaging system to, from the image of the limbus, determine the center of the limbus of the patient's eye in the external-coordinate system, and, from the image of the reflection, determine when the position of the reflection is coincident with the center of the limbus, at which position an axis normal to the cornea defines the reference axis. |