Retinal Cells Scattering Light Source Polarization

The human's eye is a biological tissue with high scattering characteristics. The intrinsic pathological features of retina tissue will be the detailed basis of clinical diagnosis and treatment, such as diabetic retinopathy, macular degeneration, retinitis pigmentosa. Based on the research of the transmission mechanism of the photon in the retina tissue, there is a necessary theoretical support for analysis and extraction of the internal characteristic parameters. The retina tissue is also the research object to the fundus camera, optical coherence tomography and the scattering spectrometer instrument etc. To figure out the scattering properties of the retina tissue will also make these testing instrument or method improved.Based on the Mie scattering theory, various parameters of single scattering problem are studied in this paper, there are three efficiency factors, albedo, anisotropy factor and the mathematical relationships between them. Combined with radiative transfer theory, the multiple scattering problems of beam transmitted in retina tissue are researched. And we discuss the influence of scattering polarization (including particles size, concentration and shape factor) with different particles. Finally, according to the anatomic structure and cellular distribution, a static structure factor from molecular dynamics is introduced to revise the radiative transfer theory, and the polarization of scattered light is numerically solved by the generalized sphere harmonic function method.The numerical results show that the polarization of the scattered light depends on the particles size, concentration distribution and cell shape. Considering the retina as the research object, light polarization fluctuates for different polar angles and optical paths, and the variance of scattered light polarization increases with the growing of scattering angle. If we only take the concentration distribution into account, cone cells has more intrinsic polarization than rod cells. And also we consider the shape factor, then the rod cells has more intrinsic polarization.