Single-camera sequential-scan-based polarization-sensitive SDOCT for retinal imaging

A single-camera, high-speed, polarization-sensitive, spectral-domain optical-coherence-tomography system was developed to measure the polarization properties of the in vivo human retina. A novel phase-unwrapping method in birefringent media is described to extract the total reflectivity, accumulative retardance, and fast-axis orientation from a specially designed sequence of polarization states incident on the sample. A quarter-wave plate was employed to test the performance of the system. The average error and standard deviation of retardation measurements were 3.2 degrees and 2.3 degrees , respectively, and of the fast-axis orientation 1.2 degrees and 0.7 degrees over the range of 0 degrees -180 degrees . The depolarization properties of the retinal pigment epithelium were clearly observed in both retardance and fast-axis orientation image. A normalized standard deviation of the retardance and of the fast-axis orientation is introduced to segment the polarization-scrambling layer of the retinal pigment epithelium.