Constrained least-squares estimation of surface curvature and dioptric power from meridional measurements

A dioptric power or surface curvature may be presumed or known to be of some particular type, for example spherical, or astigmatic and with a particular nearest equivalent sphere. Such knowledge or presumption represents a constraint on the power or curvature. This paper shows how meridional measurements can be used to obtain least-squares estimates of surface curvature or dioptric power under the constraint.