optical coherence tomograph

In this study, we present an optical coherence tomographic angiography (OCTA) prototype using a 500 kHz high-speed swept-source laser. This system can generate a 75-degree field of view with a 10.4 µm lateral resolution with a single acquisition. With this prototype we acquired detailed, wide-field, and plexus-specific images throughout the retina and choroid in eyes with diabetic retinopathy, detecting early retinal neovascularization and locating pathology within specific retinal slabs. Our device could also visualize choroidal flow and identify signs of key biomarkers in diabetic retinopathy...

BACKGROUND: Among the two stent strategies, contemporary evidence favors double kissing crush technique (DKC) for complex unprotected distal left main bifurcation (UdLMB) lesions. However one of the major challenges to these lesions is side branch (SB) restenosis. AIMS: Our aim was to identify optical coherence tomographic (OCT) characteristics that may predict SB restenosis (SBR) after UdLMB angioplasty using DKC technique. METHODS: This was a single-center, retrospective study that included 60 patients with complex UdLMB disease, who underwent OCT-guided angioplasty using DKC technique...

PURPOSE: The aim of this study was to analyze corneal topography relative to astigmatism, higher order aberrations, and corneal curvatures in Terrien marginal degeneration using 3-dimensional anterior-segment optical coherence tomography. METHODS: Twenty-nine eyes of 15 Finnish patients from a tertiary referral center had topographic axial power maps classified into 4 patterns by visual grading: crab claw (CC), mixed (M), arcuate (A), and normal. Regular astigmatism, keratometry, higher order aberrations, maximal corneal thinning, apex thickness, and curvature changes relative to best fit sphere toward maximal peripheral thinning were compared...

This article reviews literature on the use of intraoperative optical coherence tomography (iOCT) in vitreoretinal surgery, describes the historical aspects of the development of this technology from portable devices to optical coherence tomographs integrated into the surgical microscope, considers the advantages, limitations and disadvantages of this technology, which are now becoming obvious due to the accumulated experience. The review also explores the prospects for the development of iOCT and possible ways to solve its problems...

PURPOSE: The study assesses the potential influence of refractive errors in keratoconus (KC) on the results of tomographic methods of studying the structures of the posterior eye segment. MATERIAL AND METHODS: The study included 30 patients with bilateral stabilized KC of stages I-IV in classification by M. Amsler. Spherical and cylindrical components of refractions were determined using automatic refractometry, keratometry measurements - based on scanning keratotopography with Scheimpflug analyzer...

PURPOSE: To evaluate the visual, refractive, and tomographic results of patients with corneal ectasia treated with corneal allogenic intrastromal ring segments (CAIRS) insertion without concomitant corneal cross-linking. METHODS: Fifty-two eyes from 39 patients with stable corneal ectasia and unsatisfactory visual acuity with contact lenses were included. All patients underwent CAIRS insertion with no concomitant corneal procedure at the American University of Beirut Medical Center between September 2019 and July 2022...

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Murine models are commonly used to study glaucoma, the leading cause of irreversible blindness in humans. Blindness in glaucoma is associated with intraocular pressure (IOP), which is generated and regulated by the tissues of the aqueous outflow pathway. One of the main components of the aqueous humor pathway are the pectinate ligaments (PLs) that connect iris and trabecular meshwork at the anterior chamber angle. However, their role in helping maintain the biomechanical stability of murine aqueous outflow pathway is unknown, thus motivating this study...

PURPOSE: To identify optical coherence tomography (OCT) features to predict the course of central serous chorioretinopathy (CSC) with an artificial intelligence-based program. METHODS: Multicenter, observational study with a retrospective design. Treatment-naïve patients with acute CSC and chronic CSC were enrolled. Baseline OCTs were examined by an artificial intelligence-developed platform (Discovery OCT Fluid and Biomarker Detector, RetinAI AG, Switzerland)...

BACKGROUND/AIM: To examine the relationship between baseline blood flow biomarkers and long-term open-angle glaucoma (OAG) progression. METHODS: 112 patients with early to moderate OAG (mean age 64.9±11.0 years; 68 female) were evaluated at baseline and every 6 months from 2008 to 2013. Biomarkers of retinal capillary blood flow were assessed by Heidelberg retinal flowmetry. Functional disease progression was monitored via Humphrey visual field examinations, defined as two consecutive visits with a mean deviation decrease ≥2 decibels and/or Advanced Glaucoma Intervention Study score increase ≥2 compared with baseline...

No abstract text is available yet for this article.

RATIONALE: Development and spontaneous closure of a macular hole (MH) in a vitrectomized eye is relatively rare. We report our findings in a case in which vitrectomy was performed successfully to treat a vitreous hemorrhage (VH), but a MH developed eight months later. The MH spontaneously closed 2 weeks later, but then reopened. A second vitrectomy was performed with insertion of the internal limiting membrane flap into the MH which led to the successful closure of the MH. The purpose of this article is to present an explanation of how MH developed in this eye without vitreous traction...

BACKGROUND: The clinical value of high-risk coronary plaque characteristics (CPCs) to inform intensified medical therapy or revascularization of non-flow-limiting lesions remains uncertain. OBJECTIVES: The authors performed a systematic review and meta-analysis to study the prognostic impact of CPCs on patient-level and lesion-level major cardiovascular adverse events (MACE). METHODS: Thirty studies (21 retrospective, 9 prospective) with 30,369 patients evaluating the association of CPCs with MACE were included...

This work compares two tomographic imaging technologies, time-domain full-field optical coherence tomography (FFOCT) working in reflection and optical transmission tomography (OTT), using a new optical setup that combines both. We show that, due to forward-scattering properties, the axial sectioning and contrast in OTT can be optimized by tuning illumination. The influence of sample scattering and thickness are discussed. We illustrate the comparison of the two methods in static (morphology) and dynamic (metabolic contrast) regimes using cell cultures, tissues and entire organisms emphasizing the advantages of both approaches...

INTRODUCTION: The aim of this work is to evaluate the intraobserver repeatability and interobserver reproducibility of corneal power measurements obtained with a swept-source optical coherence tomographer (CASIA 2, Tomey, Japan) in healthy subjects. METHODS: A total of 67 right eyes from 67 healthy subjects were enrolled. Two experienced observers measured each eye three times consecutively with the CASIA 2. Corneal power values were recorded as simulated keratometry, anterior, posterior, and total corneal power...

INTRODUCTION: This study evaluated the differences and agreement between a new Scheimpflug camera (Scansys) and a swept-source anterior segment optical coherence tomographer (CASIA 2) for measurements of the anterior segment of the eye in normal subjects. METHODS: This prospective study included 84 eyes from 84 normal adult subjects who underwent three consecutive measurements with the Scansys and the CASIA 2 in random order. The mean keratometry (Km), astigmatism magnitude (AST), J0 , and J45 vectors for both anterior and posterior corneal surfaces, central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior chamber depth (ACD) were obtained by both devices...

PURPOSE: To report our findings in a patient with a two layered dome shaped macula (DSM) in which only the inner layer of the sclera protruded anteriorly. OBSERVATIONS: An 84-year-old woman with high myopia had a DSM in both eyes. The optical coherence tomographic (OCT) image of the left eye showed a uniform thickening of the foveal sclera, but the DSM of the right eye was split into an inner and outer layer by intrascleral blood vessels running between the two layers...

Optical diffraction tomography (ODT) solves an inverse scattering problem to obtain label-free, 3D refractive index (RI) estimation of biological specimens. This work demonstrates 3D RI retrieval methods suitable for partially-coherent ODT systems supported by intensity-only measurements consisting of axial and angular illumination scanning. This framework allows for access to 3D quantitative RI contrast using a simplified non-interferometric technique. We consider a traditional iterative tomographic solver based on a multiple in-plane representation of the optical scattering process and gradient descent optimization adapted for focus-scanning systems, as well as an approach that relies solely on 3D convolutional neural networks (CNNs) to invert the scattering process...

BACKGROUND: Epiretinal membranes (ERM) represent one of the most common findings in retinal examination. Structural changes of the retinal layers in patients with ERM can be visualized and classified using OCT. The purpose of this study is to evaluate structural and functional changes related to surgical treatment of ERM. METHODS: Monocentric retrospective analysis of 92 patients who underwent 23-gauge-pars plana vitrectomy (ppV) combined with cataract surgery for idiopathic ERM from 2015 to 2020...

PURPOSE: To determine the longitudinal changes in the morphologic features of dome-shaped macula (DSMs) in highly myopic eyes. METHODS: Patients with a DSM and high myopia (spherical equivalent <-8 diopters [D] or axial length ≥26.5 mm) were retrospectively studied. The medical records, optical coherence tomographic (OCT) images, and ultra-widefield OCT images were analyzed. RESULTS: A total of 113 eyes of 82 patients were studied with a mean follow-up of 122...