A Numerical Test of the Normal Incidence Uniaxial Model of Corneal Birefringence

Donohue, D. J.; Stoyanov, B. J.; McCally, Russell L.; Farrell, Richard A.

doi:10.1097/00003226-199605000-00009

Cited by 11 publications

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“…The four Stokes parameters are denoted as and . The parameter represents the total light intensity ( ) backreflected from the eye at each position and is independent of the polarization state: (1) represents the difference between the intensities of light linearly polarized at 0 ( ) and 90 ( ), normalized to the total intensity: (2) represents the difference in intensities of light linearly polarized at 45 and 45 normalized to the total intensity: (3) represents the difference in intensities of right ( ) and left ( ) circular polarized light, normalized to the total intensity: (4) Gray scale images of the , and Stokes parameters are presented. In the image pixel brightness is proportional to the local value of in dB.…”

Section: A Psoct Principle and Setupmentioning

confidence: 99%

Polarization sensitive optical coherence tomography of the rabbit eye

Ducros

Boer

Huang

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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A polarization-sensitive optical coherence tomography (PSOCT) system was used to acquire depth-resolved images of the Stokes parameters of light backreflected from ex vivo rabbit eyes. The light backreflected from the eye interferes with that from the reference arm and is coherently detected in two orthogonal polarization channels. The two signals are digitized and the four Stokes parameters (I; Q; U; I ; Q; U; I ; Q; U; and V V V) of the backreflected light are computed for light backreflected from each longitudinal/lateral position in the eye. From the measured Stokes parameters, an estimate of the relative phase retardation between the two orthogonal polarizations can be determined. Two eyes were enucleated, imaged within 6-h postmortem and histology performed. Images of the Stokes parameters of light backreflected from the corneal stroma show significant local variations in the polarization state, possibly due to local changes in stromal structure. Depth-resolved Stokes parameter images of light backreflected from the retina were also acquired. A birefringent layer was observed at the position consistent with the known location of the nerve fiber layer (NFL). The local thickness of the birefringent layer determined with PSOCT was in good agreement with values determined histologically.

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Section: A Psoct Principle and Setupmentioning

confidence: 99%

Polarization sensitive optical coherence tomography of the rabbit eye

Ducros

Boer

Huang

et al. 1999

IEEE J. Select. Topics Quantum Electron.

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show abstract

“…12 Several models have been proposed to explain this behavior of corneal birefringence. 7,8,[13][14][15][16][17][18] Most of these models agree that birefringence is at its minimum at the center of the cornea and increases monotonically toward the peripheral regions of the cornea. These models also indicate that the effective birefringence increases as the angle of incidence with respect to the surface normal of the cornea increases.…”

Section: Introductionmentioning

confidence: 98%

Dual-wavelength polarimetric glucose sensing in the presence of birefringence and motion artifact using anterior chamber of the eye phantoms

2013

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Abstract. Noninvasive glucose monitoring is being investigated as a tool for effectively managing diabetes mellitus. Optical polarimetry has emerged as one such method, which can potentially be used to ascertain blood glucose levels by measuring the aqueous humor glucose levels in the anterior chamber of the eye. The key limitation for realizing this technique is the presence of sample noise due to corneal birefringence, which in the presence of motion artifact can confound the glucose signature in the aqueous humor of the eye. We present the development and characterization of a real-time, closed-loop, dual-wavelength polarimetric system for glucose monitoring using both a custom-built plastic eye phantom (in vitro) and isolated rabbit corneas (ex vivo) mounted in an artificial anterior chamber. The results show that the system can account for these noise sources and can monitor physiologic glucose levels accurately for a limited range of motion-induced birefringence. Using the dual-wavelength system in vitro and ex vivo, standard errors were 14.5 mg∕dL and 22.4 mg∕dL, respectively, in the presence of birefringence with motion. The results indicate that although dual-wavelength polarimetry has a limited range of compensation for motion-induced birefringence, when aligned correctly, it can minimize the effect of time-varying corneal birefringence for a range of motion larger than what has been reported in vivo.

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“…The birefringence of the eye is well documented in literature and numerous investigators have studied and developed models for corneal birefringence. 3,4,5,6,7,8,9,10,11 Unfortunately for us, these models are based on the transmission of light through excised and fixated cornea in vitro, [3][4][5][6][7]12 or by in vivo imaging of back reflected light that has traversed through the apex of the cornea and reflected off the inner structures, e.g. iris, retina, lens.…”

Section: Introductionmentioning

confidence: 99%

Modeling the rabbit's eye with the Mueller matrix for birefringent properties

2003

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The effect of changing corneal birefringence, due to motion artifact, remains a major obstacle to the development of an accurate non-invasive polarimetric glucose sensor for patients with diabetes mellitus. Consequently, there is still a need to characterize fully, and to quantify the relative changes in corneal birefringence to facilitate the optimization of detection algorithms, enabling in vivo accuracy within 10mg/dl. In this paper, we present preliminary results, utilizing a Mueller matrix imaging technique, that demonstrates notable relative changes in the apparent retardance and in the apparent fast axis location of rabbit cornea.

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A Numerical Test of the Normal Incidence Uniaxial Model of Corneal Birefringence

Cited by 11 publications

References 0 publications

Polarization sensitive optical coherence tomography of the rabbit eye

Polarization sensitive optical coherence tomography of the rabbit eye

Dual-wavelength polarimetric glucose sensing in the presence of birefringence and motion artifact using anterior chamber of the eye phantoms

Modeling the rabbit's eye with the Mueller matrix for birefringent properties

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