Surface model of an ophtalmic lens

摘要

The model has a prism reference point and a prescription point on the complex surface of the lens, and a normal vector to the complex surface at the prism reference point. The local characteristics is supplied inside a circular disc (10) around the prescription point and has characteristics within a circular patch centered on the prescription point and having the diameter greater than or equal to two millimeter. An Independent claim is also included for a method for calculating the prescription surface of a semi-finished lens.