The role of the macular pigment in the detection of polarized light

Abstract A direct comparison technique for measuring the dichroism responsible for the Haidinger brush effect is described, together with a subsidiary method for assessing the birefringence of the cornea. It is shown that when this birefringence is taken into account, the results are consistent with the theory of a symmetrical arrangement of a fraction of the macular pigment molecules. Tests on a number of subjects indicated that they all possessed similar areal densities of such symmetrically arranged molecules.