Optical quality of the eye lens surfaces from roughness and diffusion measurements

The Purkinje-Sanson images and the image of the anterior lens surface, formed by coherent light, are studied in this paper. The roughness and the diffusing behavior of the anterior lens surface are studied by two complementary methods: measurement of the scattering halo in the third Purkinje image and speckle-contrast measurements in the image of the anterior surface (lens epithelium). The scattering properties of the anterior lens surface are represented by an equivalent Gaussian diffusing surface defined by the standard deviation of the surface height, sigma h = 0.143 micron, and the correlation length, r0 = 7 microns. The relative contribution of this surface to the intraocular scattering has been evaluated, and it depends strongly on the age of the subjects.