1. A System for determining the orientation of the eye consisting of the following sub-systems: an x, y high-speed eye tracking system, for measuring the very fast translation or saccadic motion of the eye, relative to an ophthalmic surgical, diagnostic or treatment device or instrument; a second position measurement system for measuring slower eye movements, such as multiple dimensions of eye position and/or position of eye parts, relative to an ophthalmic surgical, diagnostic or treatment device or instrument; and a system for combining the measurements of the two previous systems for obtaining a multiple dimensional model of the eye position that is more accurate than the model obtainable from either system individually.