title: High-sensitivity determination of birefringence in turbid media with enhanced polarization-sensitive optical coherence tomography.
abstract: Polarization-sensitive optical coherence tomography provides high-resolution cross-sectional characterization of birefringence in turbid media. Weakly birefringent biological tissues such as the retinal nerve fiber layer (RNFL) require advanced speckle noise reduction for high-sensitivity measurement of form birefringence. We present a novel method for high-sensitivity birefringence quantification by using enhanced polarization-sensitive optical coherence tomography (EPS-OCT) and introduce the polarimetric signal-to-noise ratio, a mathematical tool for analyzing speckle noise in polarimetry. Multiple incident polarization states and non-linear fitting of normalized Stokes vectors allow determination of retardation with +/-1 degrees uncertainty with invariance to unknown unitary polarization transformations. Results from a weakly birefringent turbid film and in vivo primate RNFL are presented. In addition, we discuss the potential of EPS-OCT for noninvasive quantification of intracellular filamentous nanostructures, such as neurotubules in the RNFL that are lost during the progression of glaucoma.
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712-1084, USA. natekemp@mail.utexas.edu
authors.forename: Nate J
authors.initials: NJ
authors.lastname: Kemp
authors.forename: Jesung
authors.initials: J
authors.lastname: Park
authors.forename: Haitham N
authors.initials: HN
authors.lastname: Zaatari
authors.forename: H Grady
authors.initials: HG
authors.lastname: Rylander
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Milner
mesh_terms: D000465:Algorithms; D000818:Animals; D001718:Birefringence; D005260:Female; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008253:Macaca mulatta; D009391:Nephelometry and Turbidimetry / Q000379:methods*; D009898:Optic Disk / Q000502:physiology* / Q000648:ultrastructure*; D012031:Refractometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*