Ellipsometry of the human retina in vivo: preservation of polarization

A new apparatus for in vivo retinal-scattering experiments incorporating Mueller-matrix ellipsometry is described. The basic principle is that the state of polarization of the entrance beam is modulated, after which the Stokes vector of the exit beam is assessed. Results show that nearly 90% of the degree of polarization of the entrance beam is preserved after double passage of the ocular media and retinal scattering. Changes in the state of polarization are studied in terms of a rotation around an eigenvector on the Poincaré sphere. These studies show that the type of change in the state of polarization of the totally polarized component is probably caused by a linearly birefringent process.