Enhancement of Lamina Cribrosa Visibility in Optical Coherence Tomography Images Using Adaptive Compensation

Mari, Jean-Martial; Strouthidis, Nicholas G.; Park, Sung Chul; Girard, M

doi:10.1167/iovs.12-11327

Cited by 110 publications

(99 citation statements)

References 30 publications

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“…6(b), this operation resulted in decreased brightness in most regions of the images. When subjective viewability matters more than the linearity of the operation, it may be effective to apply nonlinear image processing for contrast enhancement such as adjustment of dynamic range, gamma correction and adaptive methods [67,68].…”

Section: Discussionmentioning

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

Biomed. Opt. Express

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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.

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Section: Discussionmentioning

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

Biomed. Opt. Express

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“…1). 29,30 Measurement was performed by using a manual caliper tool in the Amira software (version 5.2.2; Visage Imaging, Berlin, Germany) at seven selected Bscan images spaced equidistantly across the vertical optic disc diameter in each eye. These seven B-scan lines were defined as planes 1 to 7 (top to bottom in Fig.…”

Section: Quantification Of Posterior Bowing Of the Lcmentioning

confidence: 99%

Reduction of the Lamina Cribrosa Curvature After Trabeculectomy in Glaucoma

Lee

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. To investigate whether the lamina cribrosa (LC) curvature is decreased after trabeculectomy.METHODS. Thirty-nine eyes of 39 patients with primary open-angle glaucoma who underwent trabeculectomy were included. Optic nerves were scanned by using enhanced-depth-imaging spectral-domain optical coherence tomography before and after trabeculectomy. The LC curvature was assessed by measuring the LC curvature index (LCCI) in seven horizontal Bscan images in each eye. RESULTS.The LCCI was significantly smaller at postoperative 6 months than at the preoperative level in all seven planes (all P < 0.001). Preoperative LCCI was associated with younger age at superior midperiphery, midhorizontal plane, inferior midperiphery (all P 0.005) and higher preoperative intraocular pressure (IOP) at superior and inferior midperiphery (both P ¼ 0.039). Younger age and larger preoperative LCCI were associated with a larger reduction of the LCCI at all three locations (P ¼ 0.003 and 0.031 at superior midperiphery, P ¼ 0.011 and 0.001 at midhorizontal plane, and P ¼ 0.014 and 0.005 at inferior midperiphery, respectively), whereas the percentage IOP lowering was associated at superior and inferior midperiphery (P ¼ 0.017 and 0.047, respectively).CONCLUSIONS. Lamina cribrosa curvature was reduced after trabeculectomy. This finding suggests that LC curvature may have value as a parameter relevant to optic nerve head biomechanics.

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“…Adaptive compensation is an OCT postprocessing technique that removes shadows and enhances contrast. It has been shown to significantly improve visibility of the anterior LC, its insertions, and other ocular structures [29][30][31][32] (Figs. 1A, 1B).…”

Section: Image Delineationmentioning

confidence: 99%

A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes

Thakku

Tham

Baskaran

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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Citation: Thakku SG, Tham Y-C, Baskaran M, et al. A global shape index to characterize anterior lamina cribrosa morphology and its determinants in healthy Indian eyes. Invest Ophthalmol Vis Sci. 2015;56:3604-3614. DOI:10.1167/iovs.15-16707 PURPOSE. Lamina cribrosa (LC) morphology could be implicated in the progression of glaucoma. To date, no established, quantifiable parameter to assess LC shape in vivo exists. We aim to introduce a new global shape index for the anterior LC (LC-GSI) and to identify associations with ocular factors in a healthy Indian population. METHODS.Optical coherence tomography (OCT) scans of the optic nerve head (ONH) were performed on 162 healthy subjects. Optic nerve head structures were delineated and a geometric characterization of anterior LC morphology was obtained by measuring curvature along 180 LC cross sections and representing it as LC-GSI ranging from À1 to þ1. Lamina cribrosa depth and curvature were also reported. Linear regression was used to identify factors associated with LC morphology.RESULTS. The typical healthy LC had a saddle rut-like appearance, with a central ridge visible in superior-inferior cross sections. A more prominent central ridge (larger LC-GSI) was associated with shorter axial length (P < 0.001), smaller Bruch's membrane opening (BMO) area (P ¼ 0.020), smaller vertical cup-to-disc ratio (VCDR) (P ¼ 0.007), and larger minimum rim width (BMO-MRW) (P ¼ 0.001). A deeper LC was associated with male sex (P < 0.001), shorter axial length (P ¼ 0.003), larger VCDR (P < 0.001), and smaller BMO-MRW (P ¼ 0.002). Age and IOP were not significantly associated with LC morphology in healthy eyes.CONCLUSIONS. The LC-GSI is a single index that quantifies overall LC shape in an intuitive way. Ocular determinants of LC-GSI in healthy eyes included risk factors for glaucoma (axial length, VCDR, and BMO-MRW), highlighting the potential role of LC morphological characterization in the diagnosis and monitoring of glaucoma.Keywords: lamina cribrosa morphology, optic nerve head, optical coherence tomography A major site of retinal ganglion cell (RGC) damage in glaucoma is at the optic nerve head (ONH), where RGC axons congregate before making their way to the brain. [1][2][3] Within the ONH, RGC axons pass through a mesh-like collagen fiber structure called the lamina cribrosa (LC), before exiting the eye.Lamina cribrosa morphology and progression of glaucoma are believed to be closely related. 4 In particular, glaucomatous onset is associated with posterior displacement of the anterior LC surface, 5-7 posterior migration of the LC insertion points, 6 and backward bowing of the entire LC. 8 Nonhuman primate models of glaucoma have also shown similar associations. 9-11Furthermore, these models suggest that LC changes precede surface level retinal nerve fiber layer (RNFL) thinning, 11,12 which is a useful marker of glaucoma onset. Taken together, these findings indicate that an assessment of LC morphology may potentially be used as a biomarker for early glaucoma detection. The...

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Enhancement of Lamina Cribrosa Visibility in Optical Coherence Tomography Images Using Adaptive Compensation

Cited by 110 publications

References 30 publications

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

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

Reduction of the Lamina Cribrosa Curvature After Trabeculectomy in Glaucoma

A Global Shape Index to Characterize Anterior Lamina Cribrosa Morphology and Its Determinants in Healthy Indian Eyes

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