Relation between meridional power and the dioptric power matrix.

The components of meridional power in any meridian can be expressed elegantly in terms of the dioptric power matrix. The form of the expressions is that which is well known in the statistical literature as a quadratic form; there are important statistical implications for dioptric power and its measurement. The relation forms the basis of the calculation and least-squares estimation of dioptric power and surface curvature from meridional measurements.