<title>Computer-based null test compensation for ophthalmic lenses</title>

Abstract

In this paper, we will describe a method used to obtain the power error distribution map for a spherical well corrected ophthalmic lens. The proposed method uses a computer to perform a null test compensation to probe the real refractive correction state of the lens under test. The Hartman test is used to probe an ophthalmic lens and subtract the ideal power distribution map corresponding to the same lens design. In this way we obtain the power error distribution map of the lens. The proposed method may be useful in mass production of spherical ophthalmic lenses.