Optical contrast enhancement of high-resolution ocular fundus imaging in vivo using polarimetry

The adaptive optics (AO) retina imaging was performed with contrast enhancement by characterizing polarization parameters of the living retina. A removable pair of polarization state generating unit near the optical source and analysis unit near the CCD camera was incorporated into the basic 37-channle deformable mirror AO microscopic ophthalmoscope. Double-pass imaging polarimetry of the human eye was carried out, then incomplete Mueller matrix was calculated and analyzed to optimize the retina imaging condition using polarized light, which caused the subretinal structures with different polarization properties to emerge from the scattering light background, so the contrast of the image could be substantially enhanced. This method is demonstrated briefly and its validity was tested in the laboratory. The high-resolution images of ocular fandus are compared with 8-frame-averaging images we obtained prior to this method. The experiment results now show improved visualization of fundus structures to some extent without greatly sacrificing image resolution.