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Macular Inner Retinal Layer Thickness in Relation to Photopic and Mesopic Contrast Sensitivity in Healthy Young and Older Subjects
摘要： PURPOSE. To examine relationships between the thicknesses of ganglion cell (GC)-related macular layers and central photopic or mesopic contrast sensitivity (CS) in healthy eyes. METHODS. Measurements were made in 38 young and 38 older healthy individuals. Total, inner, layer (IRL) thicknesses were measured in the macula region through and outer retinal spectral-domain optical coherence tomography (SD-OCT) across three sub?elds, or rings, centered at the fovea: central foveal, pericentral, and peripheral. Ganglion cell complex and circumpapillary retinal nerve ?ber layer thicknesses were also measured. Low-spatial-frequency CS for gratings presented at the central 108 visual ?eld were measured through computerized psychophysical tests under photopic and mesopic conditions. Relationships were examined by uni- and multivariate regression analysis. RESULTS. Peripheral IRL thickness emerged as the only independent predictor of photopic CS (P ? 0.001) in the young group and of photopic (P ? 0.026) and mesopic CS (P ? 0.001) in the older group. The slopes of regression lines used to predict CS from peripheral IRL thickness were signi?cantly different for pair-wise comparisons of both photopic CS and age group (P ? 0.0001) and mesopic CS (P ? 0.0001) and age group. These models explained 37% of the variability in photopic CS and 36% of the variability in mesopic CS. CONCLUSIONS. Macular IRL thinning likely due to GC loss was related to reduced photopic and mesopic CS in older healthy eyes. In contrast, in the young eyes, a thicker macular IRL, possibly indicating transient gliosis, was associated with reduced CS.
关键词： contrast sensitivity,optical coherence tomography,retinal ganglion cells,macular inner retinal layer thickness,mesopic vision,glial cells
更新于2025-09-04 15:30:14
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Full-Field Optical Coherence Tomography as a Diagnosis Tool: Recent Progress with Multimodal Imaging
摘要： Full-?eld optical coherence tomography (FF-OCT) is a variant of OCT that is able to register 2D en face views of scattering samples at a given depth. Thanks to its superior resolution, it can quickly reveal information similar to histology without the need to physically section the sample. Sensitivity and speci?city levels of diagnosis performed with FF-OCT are 80% to 95% of the equivalent histological diagnosis performances and could therefore bene?t from improvement. Therefore, multimodal systems have been designed to increase the diagnostic performance of FF-OCT. In this paper, we will discuss which contrasts can be measured with such multimodal systems in the context of ex vivo biological tissue examination. We will particularly emphasize three multimodal combinations to measure the tissue mechanics, dynamics, and molecular content respectively.
关键词： dynamics,multimodality,cellular metabolism,?uorescence microscopy,biomechanics,mechanical properties,full-?eld optical coherence tomography
更新于2025-09-04 15:30:14
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Propagation of Optical Coherence Vortex Lattices in Turbulent Atmosphere
摘要： Propagation properties in the turbulence atmosphere of the optical coherence vortex lattices (OCVLs) are explored by the recently developed convolution approach. The evolution of spectral density distribution, the normalized M2-factor, and the beam wander of the OCVLs propagating through the atmospheric turbulence with Tatarskii spectrum are illustrated numerically. Our results show that the OCVLs display interesting propagation properties, e.g., the initial Gaussian beam distribution will evolve into hollow array distribution on propagation and ?nally becomes a Gaussian beam spot again in the far ?eld in turbulent atmosphere. Furthermore, the OCVLs with large topological charge, large beam array order, large relative distance, and small coherence length are less affected by the negative effects of turbulence. Our results are expected to be used in the complex system optical communications.
关键词： optical coherence vortex lattices,evolution properties,atmospheric turbulence,free-space optical communications
更新于2025-09-04 15:30:14
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Current OCT Approaches Do Not Reliably Identify TCFAs
摘要： It is now clearly established that Thin-Capped Fibroatheromas (TCFAs) lead to most Acute Coronary Syndromes (ACSs). The ability to selectively intervene on TCFAs predisposed to rupture and ACSs would dramatically alter the practice of cardiology. While the ability of OCT to identify thin walled plaques at micron scale resolutions has represented a major advance, it is a misconception that it can reliably identify TCFAs. One major reason is that the ‘diffuse border’ criteria currently used to determine ‘lipid plaque’ is almost undoubtedly from high scattering in the intima and not because of core composition (necrotic core). A second reason is that, rather than looking at lipid collections, studies need to be focused on identifying necrotic cores with OCT. Necrotic cores are characteristic of TCFAs and not lipid collections. Numerous other OCT approaches are available which can potentially accurately assess TCFAs, but these have not been aggressively pursed which we believe likely stems in part from the misconceptions over the efficacy of ‘diffuse borders’.
关键词： Myocardial infarction,Optical coherence tomography: OCT,Macrophages,Plaque rupture,Acute coronary syndrome: ACS,Thin capped fibroatheroma: TCFA,Lipid,Massachusetts General Hospital Lightlab
更新于2025-09-04 15:30:14
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Retinal and Optic Disc Alterations in Alzheimer ’s Disease: the Eye as a Potential Central Nervous System Window
摘要： Pathologic changes in the retina and optic nerve are observed in patients with Alzheimer′s disease (AD), even in early stages of the dementia. In our clinical ophthalmology practice, we use optical coherence tomography (OCT), a noninvasive, rapid, objective, and reliable technology that enables for quantification of the retinal nerve fiber layer (RNFL), namely the retinal ganglion cell axons that eventually form the optic nerve. The opportunity to analyze a part of the central nervous system by such a simple exploration led to several studies demonstrating thinning of the RNFL and central retina in AD patients compared with healthy subjects. Here we present some of our investigations in AD patients using Spectral Domain-OCT. Our results suggest that axonal loss secondary to pathologic alterations in the brains of AD patients can be observed by OCT. We also analyzed the association between retinal and RNFL thicknesses and neurologic characteristics, disease duration and severity, and found that mean RNFL thickness was significantly correlated with disease duration, indicating that the progression of AD is associated with a progressive loss of ganglion cells.
关键词： Retinal nerve fiber layer,Retinal thickness,Optic disc,Optical coherence tomography,Alzheimer’s disease
更新于2025-09-04 15:30:14
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[Lecture Notes in Computer Science] Intravascular Imaging and Computer Assisted Stenting and Large-Scale Annotation of Biomedical Data and Expert Label Synthesis Volume 11043 (7th Joint International Workshop, CVII-STENT 2018 and Third International Workshop, LABELS 2018, Held in Conjunction with MICCAI 2018, Granada, Spain, September 16, 2018, Proceedings) || Deep Learning-Based Detection and Segmentation for BVS Struts in IVOCT Images
摘要： Bioresorbable Vascular Sca?old (BVS) is the latest stent type for the treatment of coronary artery disease. A major challenge of BVS is that once it is malapposed during implantation, it may potentially increase the risks of late stent thrombosis. Therefore it is important to analyze struts malapposition during implantation. This paper presents an automatic method for BVS malapposition analysis in intravascular optical coherence tomography images. Struts are ?rstly detected by a detector trained through deep learning. Then, struts boundaries are segmented using dynamic programming. Based on the segmentation, apposed and malapposed struts are discriminated automatically. Experimental results show that the proposed method successfully detected 97.7% of 4029 BVS struts with 2.41% false positives. The average Dice coe?cient between the segmented struts and ground truth was 0.809. It concludes that the proposed method is accurate and e?cient for BVS struts detection and segmentation, and enables automatic malapposition analysis.
关键词： Bioresorbable vascular sca?old,Deep learning,Intravascular optical coherence tomography,Detection and segmentation
更新于2025-09-04 15:30:14
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Voltage Noise and Jitter Analysis for Swept Source Optical Coherence Tomography using KTa1-xNbxO3 Deflector
摘要： This paper describes voltage noise and jitter analysis for the depth deviation of a point spread function in a swept source optical coherence tomography system using a KTa1-xNbxO3 deflector. An interference waveform with voltage noise and jitter was simulated according to a previous report. Typical values for the voltage noise ΔVTYP and jitter ΔtTYP were also obtained from a previous report and experiment. It was determined that the depth deviation is limited by the ΔtTYP of the system. Therefore, the quality of the tomographic image can be efficiently improved by reducing jitter.
关键词： Interference waveform,Jitter,Simulation,Swept source optical coherence tomography,Signal-to-noise ratio,Voltage noise
更新于2025-09-04 15:30:14
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Vitrectomy for diabetic macular edema: optical coherence tomography criteria and pathology of the vitreomacular interface
摘要： Purpose: To correlate spectral-domain optical coherence tomography (SD-OCT) criteria and clinical data with pathology of the vitreomacular interface (VMI) in eyes with diabetic macular edema (DME). Design: Retrospective cross-sectional study and laboratory investigation. Methods: We included specimens of 27 eyes of 26 patients with center-involved DME that underwent vitrectomy with peeling of the internal limiting membrane (ILM). Selection of specimens was consecutive and in retrospect using our register of the Vitreoretinal Pathology Unit. Clinical data and SD-OCT examinations were correlated to immunocytochemistry and transmission electron microscopy. Classification of DME comprised sponge-like diffuse retinal thickening, cystoid macular edema, and serous retinal detachment. VMI was evaluated for presence of epiretinal membrane (ERM) and thickened vitreous cortex (tVC). Results: ERMs and tVC were found in all DME types. Diffuse DME showed more often tVC than cystoid DME. Hyalocytes, contractile myofibroblasts, glial cells, matrix metalloproteinases-2 and -9, and collagen type I, II and III were positive tested irrespective of DME type. There were no significant cell fragments at the retinal side of ILM. Visual acuity improved in the majority of cases and macular thickness decreased significantly during mean follow-up of 17 ± 10 months. Conclusions: All eyes presented pathologic VMI changes irrespective of the OCT classification of DME type or presence of ERM. Composition of fibrocellular membranes at the VMI indicated remodelling of vitreous cortex and transdifferentiation of hyalocytes into myofibroblasts. Our findings might argue for an early surgical intervention in eyes with DME irrespective of the presence of traction formation imaged by SD-OCT.
关键词： optical coherence tomography,diabetic macular edema,vitrectomy,pathology,vitreomacular interface
更新于2025-09-04 15:30:14
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Imaging and visualization of the polarization state of the probing beam in polarization-sensitive optical coherence tomography
摘要： We propose a simple and ef?cient method of color-encoded Stokes parameters to visualize the polarization states for polarization-sensitive optical coherence tomography (PS-OCT) of biological tissue. In this method, polarization states of the probing light are detected and described in the Stokes domain. Three primary colors of red, green, and blue are used to code Stokes parameters of Q, U, and V, respectively, which can be used to represent and visualize each unique polarization state. A strategy that uses the polarization state as the PS-OCT imaging parameter is ?rst introduced to obtain high contrast images of the birefringent samples. Then, color-based automatic segmentation of birefringent components from 3D scanned tissue volume is proposed to isolate the network of the 3D nerve bundles in a mouse brain without cutting the brain into slices. Experimental validation and demonstrations are given by imaging ex vivo mouse tail and brain tissues to show the usefulness of proposed polarization state imaging and segmentation methods.
关键词： automatic segmentation,Stokes parameters,birefringent tissue,polarization-sensitive optical coherence tomography,polarization state imaging
更新于2025-09-04 15:30:14
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Optic nerve head width and retinal nerve fiber layer changes are good indexes for validating the successful induction of experimental anterior ischemic optic neuropathy
摘要： Reproducible skills are essential for successful induction of a rat model of anterior ischemic optic neuropathy (rAION). We established an in vivo validation index by measuring the natural course of optic nerve head (ONH) width and retinal nerve fiber layer (RNFL) thickness in the rAION model using optical coherence tomography (OCT). The rAION model was induced by photodynamic operations. We measured the ONH width and RNFL thickness in the acute stage (<3 days), subacute stage (day 7 and day 14) and later stage (day 28) post-infarct by OCT. RNFL were measured by hematoxylin and eosin stain (HE) to confirm the OCT findings. The RGCs survival rate was determined by retrograde Fluoro-gold labeling, and the visual function was assessed with flash visual-evoked potentials (FVEPs) 4 weeks post-infarct. The ONH showed significant swelling in the acute stage, which also correlated with RNFL swelling. The swelling was reduced to normal within one-week post-infarct. The rAION group (0.51± 0.12 mm2) showed a significant RNFL thinning when compared with sham groups (0.92±0.15 mm2, p<0.05) on day-28 post-infarct. And HE-stained retina cross sections also showed RNFL thinning, which further confirmed our OCT Findings. The RGC density and P1-N2 amplitude were significantly reduced in rAION. Swelling, reduction of swelling, and atrophy of RNFL in acute, sub-acute, and later stage, respectively, are important events for confirming the successful induction of rAION. They suggest that the longitudinal OCT data provides a reliable index for validating the reproducibility and correct order of rAION.
关键词： optic nerve head (ONH),retinal ganglion cells (RGCs),optical coherence tomography (OCT),anterior ischemic optic neuropathy in rats (rAION),retina nerve fiber layer (RNFL)
更新于2025-09-04 15:30:14