A matrix formulation of spectacle magnification.

The paraxial 4 x 4 astigmatic system matrix is used to derive a 2 x 2 blurred-image magnification matrix, as well as a 2 x 2 spectacle magnification matrix. The 2 x 2 spectacle magnification matrix describes the meridional magnifications for any spherocyclindrical spectacle correction including a bitoric eikonic lens. The 2 x 2 spectacle magnification matrix can be approximated by the product of 2 x 2 power and shape factor matrices that have algebraic forms exactly analogous to the power and shape factor equations for spherical correcting lenses.