Analysis of phase retardation in the primate retinal nerve fiber layer by polarization sensitive optical coherence tomography

This paper presents an algorithm to analyze phase retardation and measure the primate retinal nerve fiber layer (RNFL) thickness from retinal images recorded by polarization sensitive optical coherence tomography (PSOCT). Analysis of the phase retardation and the thickness of the RNFL begins with calculating the Stokes parameters from the horizontal magnitude, vertical magnitude and relative phase difference between interference fringes of light back scattered from the retina. Stokes parameters are used to find the fast axis in the retina. We obtain phase retardation of the retinal nerve fiber layer from the computed Stokes parameters and fast axis. A map of RNFL thickness can be created with boundary detection. Finally a map of the phase retardation per unit depth (PR/UD) is calculated by dividing the linear phase retardation by local RNFL thickness.