Analysis of optimum conditions of depolarization imaging by polarization-sensitive optical coherence tomography in the human retina

Abstract

Measurement and imaging of depolarization by polarization-sensitive optical coherence tomography (PS-OCT) requires averaging of Stokes vector elements within two- or three-dimensional (3-D) evaluation windows to obtain the degree of polarization uniformity (DOPU). By use of a PS-OCT system with an integrated retinal tracker, we analyze optimum conditions for depolarization imaging, data processing, and segmentation of depolarizing tissue in the human retina. The trade-offs between figures of merit like DOPU imaging sensitivity, efficiency, and susceptibility are evaluated in terms of 3-D resolution. The results are used for a new, detailed interpretation of PS-OCT high-resolution images of the human retinal pigment epithelium and Bruch’s membrane.

Melanin Pigmentation in Rat Eyes: In Vivo Imaging by Polarization-Sensitive Optical Coherence Tomography and Comparison to Histology

“…41 Also, the use of threedimensional and temporal kernels for DOPU calculation can enable higher spatial resolution in the DOPU images. 42,43 In addition to in vivo imaging of depolarization by PS-OCT, histologic serial sections were investigated. No melanin pigments were observed in histologic sections of albino rat eyes.…”

Polarization-sensitive optical coherence tomography imaging of the anterior mouse eye

“…A variety of different algorithms have been developed to perform DOPU analysis including two-and three-dimensional (3-D) kernels as well as temporal Stokes vector averaging. 41,45,51,52 One limitation of DOPU is its inaccuracy in case of pixels with low signal-to-noise ratio (SNR). Makita et al 46 recently proposed an approach to DOPU, which eliminates the noise bias for the first two Stokes vector elements before averaging, viz.…”

Use of combined polarization-sensitive optical coherence tomography and Mueller matrix imaging for the polarimetric characterization of excised biological tissue

“…Damage of leaflet structure with collagenase was identified by decomposing the depolarization parameter of the Mueller matrix, showing the tissue had less of a randomizing (lower attenuation coefficient) effect on polarized light backscattered from the leaflet. Several authors are using the DOPU for automatic segmentation of the retinal pigmented epithelium 57,58 and other depolarizing structures. This seems counterintuitive, as the Jones calculus does not account for depolarization yet these authors consider the random polarization state of the resulting speckle as causing the DOP to be lower than 1.…”

“…In our case, the window was 10 pixels × 10 pixels, similar to what was used by others. 58 The total depolarization of the treated and untreated sample relates positively to the DOPU, as both metrics are higher in the untreated sample. While the total depolarization is cumulative the DOPU can be studied over depth as shown in Fig.…”