Null test compensators for ophthalmic lenses

Testing methods commonly used for ophthalmic lenses produce a power distribution map that treats the lens as an independent element. This map, however, does not necessarily correspond to the refractive correction state of the lens when the observer looks through it. We describe a method to obtain a refractive correction map of an ophthalmic lens, which is an improved representation of its actual performance. (C) 2002 Society of Photo-Optical instrumentation Engineers.