Also, the normal vector necessary to calculate the 2nd refraction process is determined by the photons incidence position into the prism faces (3rd position: [x.sub.2],[y.sub.2]).
5, after the incidence vector, the point of intersection with the prism face and the ensuing normal vector are determined, the direction vector of photons that passed through the prism can be calculated by the second refraction process with the same method as the first refraction process.
In order to design the individualised lenses, not only are the lens values determined in the traditional subjective
refraction process, but the objectively measured data of the i.Profiler is also used.