Imaging Polarimetry in Age-Related Macular Degeneration

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Estimation of polarimetric parameters has been a fundamental issue to assess biological tissues that have form birefringence or polarization scrambling in polarizationsensitive optical coherence tomography (PS-OCT). We present a mathematical framework to provide a maximum likelihood estimation of the target covariance matrix and its incoherent target decomposition to estimate a Jones matrix of a dominant scattering mechanism, called Cloude-Pottier decomposition, thereby deriving the phase retardation and the optic axis of the sample. In addition, we introduce entropy that shows the randomness of the polarization property. Underestimation of the entropy at a low sampling number is mitigated by asymptotic quasi maximum likelihood estimator. A bias of the entropy from random noises is corrected to show only the polarization property inherent in the sample. The theory is validated with experimental measurements of a glass plate and waveplates, and applied to the imaging of a healthy human eye anterior segment as an image filter.

Section: Estimation Of H Noise At a Single Depthmentioning

confidence: 99%

Estimation of Jones matrix, birefringence and entropy using Cloude-Pottier decomposition in polarization-sensitive optical coherence tomography

Yamanari¹,

Tsuda²,

Kokubun³

et al. 2016

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“…Polarization-sensitive OCT (PS-OCT), which is one of the functional extensions of OCT, can improve the image contrast of OCT by imaging birefringence of biological fibrous tissues [4]. PS-OCT has been demonstrated to discriminate between ocular tissues using their birefringence properties in studies on the posterior segment of the eye, retinal nerve fiber [5,6] and scar tissue in age-related macular degeneration [7,8]. Simultaneous polarization scrambling measurements discriminated the retinal pigment epithelium from other structures [7,9].…”

Section: Introductionmentioning

confidence: 99%

Birefringence measurement of cornea and anterior segment by office-based polarization-sensitive optical coherence tomography

Lim

Yamanari

Fukuda

et al. 2011

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Abstract:We present a case series of cornea and anterior segment disorders investigated by an office-based polarization-sensitive optical coherence tomography (PS-OCT). Blebs of glaucoma patients treated by trabeculectomy, and corneas of keratoconus and keratoplasty patients were measured by PS-OCT. Birefringence formations in trabeculectomy bleb were measured in 1 control eye and 3 eyes of trabeculectomy model rabbits. Polarization insensitive scattering OCT and the depth-resolved birefringence were measured simultaneously by PS-OCT. Abnormal birefringence was observed in keratoconus cases with advanced thinning and with a rupture of Descemet's membrane. The graft-host interface of the keratoplasty case showed abnormal birefringence. The appearance of abnormal birefringence in the cornea was likely to be an indication of crosslinking of collagen fibrils. The measurement of rabbit showed abnormal birefringence in the scarring eyes. Wide regions of strong birefringence were observed in the eyes of trabeculectomy patients who had high intraocular pressure. Visualization of scarring in bleb by PS-OCT may be useful for the planning of secondary surgery. PS-OCT showed promising for the study and diagnosis diseases related to abnormal fibrous tissues of the cornea and anterior eye segment.

“…On the other hand, PS-OCT measures the polarization properties of a sample [10,11,[13][14][15]. As an ophthalmic application, it has been utilized to visualize fibrous tissues [23,24] and the retinal pigment epithelium (RPE) [25,26].…”

Section: Introductionmentioning

confidence: 99%

“…It properly explains why the PSFs presented in Section 5.1 are equally good no matter whether the modulation phase correction was applied separately or not for the buffered and unbuffered modes. Equation (24) suggests that the dispersion correction can be performed at once for buffered and unbuffered spectra if the system polarization is properly aligned. However, in practice, the polarization properties of optical fibers varies slowly but continuously.…”

mentioning

confidence: 99%

Optically buffered Jones-matrix-based multifunctional optical coherence tomography with polarization mode dispersion correction

Hong

Makita

Sugiyama

et al. 2014

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Polarization mode dispersion (PMD) degrades the performance of Jones-matrix-based polarization-sensitive multifunctional optical coherence tomography (JM-OCT). The problem is specially acute for optically buffered JM-OCT, because the long fiber in the optical buffering module induces a large amount of PMD. This paper aims at presenting a method to correct the effect of PMD in JM-OCT. We first mathematically model the PMD in JM-OCT and then derive a method to correct the PMD. This method is a combination of simple hardware modification and subsequent software correction. The hardware modification is introduction of two polarizers which transform the PMD into global complex modulation of Jones matrix. Subsequently, the software correction demodulates the global modulation. The method is validated with an experimentally obtained point spread function with a mirror sample, as well as by in vivo measurement of a human retina.