Visionix

Corneal thickness measurements with the RTVue, Casia-2, and Pentacam devices in patients with mild-to-moderate keratoconus: a comparative study

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Background To compare the characteristics of corneal thickness measurements among the RTVue, Casia-2, and Pentacam in patients with mild-to-moderate keratoconus. Methods We recruited 46 eyes of 46 patients diagnosed with mild-to-moderate keratoconus at our hospital between January and March 2022. The central corneal thickness (CCT) and thinnest corneal thickness (TCT) were measured using two optical coherence tomography (OCT) instruments (RTVue and Casia-2) and the more conventional Pentacam. Differences and correlations between the CCTs and TCTs, based on the device and influencing factors, were explored. Results The CCTs were highly consistent among the groups (p = 0.434) and correlated with one another (p < 0.001). The TCTs measured by OCTs were thinner than those measured by the Pentacam (p < 0.001); however, all three devices were highly correlated (p < 0.001). The thinnest point location measurements with RTVue and Casia-2 differed significantly from ...

Retinochoroidal microvascular changes in newly developed obese children: an optical coherence tomography angiography study

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Background: Childhood obesity was associated with retinochoroidal microvascular changes using optical coherence tomography angiography (OCTA), but obesity duration was neglected. Obesity is chronic and progressive and obesity duration is related to microvascular function. Thus, it is important to identify microvascular changes in obese children timely to allow possible interventions with the increase in the number of obese children. This pilot study aimed to characterize retinochoroidal microvascular changes in newly developed obese children compared to age- and sex-matched controls. Methods: Forty newly developed obese children and 40 age- and sex-matched controls were recruited. All subjects completed comprehensive eye examinations, including axial length, cycloplegic refraction, optical coherence tomography angiography scans (AngioVue; Optovue Inc), etc. RESULTS: There were no statistically significant differences between groups in terms of month age (P = 0.927), spherical equiva...

Macular thickness and its associated factors in a Chinese rural adult population: the Handan Eye Study

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Purpose To describe the normal macular thickness and assess its associations. Methods The Handan Eye Follow-up Study was conducted between 2012 and 2013. Macular thickness was scanned by spectral-domain optical coherence tomography (OCT). The built-in software generated a retinal thickness (RT) map, which was divided into three regions (central, internal and external regions) and nine quadrants (one in central and four in internal and external regions each). Results For 5394 subjects in the Handan Eye Follow-up Study, 4793 received OCT examination, 2946 of whom (accounting for 61.46% of the total subjects, mean age 58.91±10.95, 55.6% were women) were included for analysis. The mean RT in central macula, inner and outer rings were (237.38 µm±23.05 µm), (309.77 µm±18.36 µm) and (278.29 µm±14.38 µm), respectively (overall difference, p<0.001). In inner ring, the RT in temporal was thinnest, followed b...

Evaluation of Lacrimal Punctal Changes by Anterior Segment Optical Coherence Tomography after Punctal Dilation Versus Punctal Plug Insertion in Cases of Inflammatory Punctual Stenosis

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Purpose . To compare simple punctal dilation versus punctal dilation augmented by insertion of Punctal Plug Insertion (PPP) with assessing the effect on resolving epiphora and punctum size improvement by an objective method, high-resolution AS-OCT imaging comparing punctal parameters of the patients before and after both techniques. Patients and Methods . It is a prospective, interventional, double-blinded controlled randomized study, which was conducted on two groups of patients, the first epiphora group (EG1 25 eyes), who had acquired punctal stenosis and epiphora and managed by simple punctal dilatation. The second epiphora group (EG2 20 eyes) who managed by punctal dilatation augmented with an application of perforated punctal plugs for two months. Spectral Domain Anterior Segment-OCT Image Acquisition. AS-OCT for lower puncti was performed using RTVue (Optovue Inc., Fermont, CA). OCT images of the width and length of the lower puncti of the participants were captured by the sam...

Normative Data and Associations of OCT Angiography Measurements of the Macula: The Singapore Malay Eye Study

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To describe the normative quantitative parameters of the macular retinal vasculature as well as their systemic and ocular associations using OCT angiography (OCTA). Design Population-based, cross-sectional study. Subjects Adults aged > 50 years were recruited from the third examination of the population-based Singapore Malay Eye Study. Methods All participants underwent a standardized comprehensive examination and spectral-domain OCTA (Optovue) of the macula. OCT angiography scans that revealed pre-existing retinal disease, revealed macular pathology , and had poor quality were excluded. Main Outcome Measures The normative quantitative vessel densities of the superficial layer, deep layer, and foveal avascular zone (FAZ) were evaluated. Ocular and systemic associations with macular retinal vasculature parameters were also evaluated in a multivariable analysis using linear regression models with generalized estimating equation models. Results We included 1184 scans (1184 eyes) of ...

The Importance of Signal Strength Index in Optical Coherence Tomography Angiography: A Study of Eyes with Pseudoexfoliation Syndrome

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Purpose: To evaluate the effect of the signal strength index (SSI) on a comparison of the vascular and structural OCT measurements between eyes with pseudoexfoliation syndrome (PXF) and healthy controls of Asian-Indian origin. Methods: In this cross-sectional study, 33 eyes of 33 PXF patients and 40 healthy eyes of 40 controls underwent OCT and OCT angiography (OCTA). Eyes with intraocular pressure (IOP) > 21mmHg, glaucomatous disc changes, or any other ocular pathology were excluded. Peripapillary vessel density (VD) and retinal nerve fiber layer (RNFL) thickness were determined from the optic disc scans. Parafoveal VD and ganglion cell complex (GCC) thickness were measured from the macular scans. These parameters were compared between the groups using mixed effect models after adjusting for clinical confounders such as IOP, as well as SSI of the scans. Results: The 2 groups were demographically similar. Average RNFL (94μm vs 100μm, p = 0.01) and GCC (91μm vs 95μm, p...

The Efficacy of Anti-VEGF Therapy for Putative or Visible CNV in Central Serous Chorioretinopathy by Optical Coherence Tomography Angiography

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Purpose . To investigate the effect and underlying mechanism of intravitreal antivascular endothelial growth factor (VEGF) in patients with putative or visible choroidal neovascularization (CNV) secondary to central serous chorioretinopathy (CSCR) with optical coherence tomography angiography (OCTA). Methods . In a retrospective cohort study, 16 eyes of 15 treatment-naïve CSCR patients were included and divided into two groups: a putative CNV group with nonhomogenous hyperreflectivity in the slab of choriocapillaris and a visible CNV group with obvious tangled vascular network in the slab of choriocapillaris in OCTA. Patients were recorded with best-corrected visual acuity (BCVA). The parameters, evaluated by OCTA, included central macular thickness (CMT), the height of subretinal fluid (SRF), the number of hyperreflective foci (HRF), and the area of putative or visible CNV. Results . Compared with the baseline, visual acuity was improved significantly at the last follow-up, an...

Multi-Center Repeatability of Macular Capillary Perfusion Density Using Optical Coherence Tomography Angiography

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Background/Aims: This study was to determine the test–retest repeatability in quantifying macular capillary perfusion density (CPD, expressed as fractal dimension) using optical coherence tomography angiography (OCTA) in a multi-center setting. Methods: OCTA data were obtained in self-reported healthy subjects from Bascom Palmer Eye Institute at the University of Miami (UM, N = 18) and the University of Pennsylvania (UPenn, N = 22). The right eye of each subject was imaged twice at the first visit and then again at an interval of one week to assess intra-visit and inter-visit repeatability. The macular area of the OCTA-derived capillary perfusion density (OCTA-CPD) was analyzed by custom-made image processing and fractal analysis software. Fractal analysis was performed on the skeletonized microvascular network to yield OCTA-CPD by box-counting to the fractal dimension (Dbox) in the superficial vascular plexus (SVP). Repeatability was assessed by three measures: within-subject...

Undetectable Macular Neovascularization on OCT Angiography in Age Related Macular Degeneration: Comparison between Different Devices

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Background and Objectives : The aim of this study was to report the characteristics of macular neovascularization (MNV) with undetectable flow on optical coherence tomography angiography (OCTA) in neovascular age related macular degeneration (nAMD), and compare them with the characteristics of detectable MNV. Materials and Methods : Patients with a diagnosis of nAMD who underwent dye imaging and OCTA in the same day were included and divided into two groups: undetectable and detectable flow on OCTA. Three OCTA devices were used, two with spectral-domain technology (AngioVue, RTVue 100xAvanti, Optovue, Freemont, CA, USA and Heidelberg OCT2 Beta Angiography Module, Heidelberg Engineering, Germany) and one swept-source OCTA (PlexElite 9000; Carl Zeiss Meditec, Inc., Dublin, CA, USA). We studied the demographics, neovascularization characteristics, and OCTA device and acquisition characteristics for both groups. Results : A global comparison between Group 1 and Group 2 was made, followe...

Optical Coherence Tomography (OCT) and Angio-OCT Imaging Techniques in Multiple Sclerosis Patients with or without Optic Neuritis

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The visual system is typically affected in multiple sclerosis (MS) patients. The most common ocular manifestation during the clinical course of the disease is optic neuritis (ON). Optical coherence tomography (OCT) is well-established tool for biomedical imaging that enables detection of retinal nerve fiber layer and ganglion cell layer thickness reduction – biomarkers of axonal damage and neuronal loss in MS. And OCT angiography (angio-OCT) is another imaging method for assessing retinal and choroidal vessels with no need of contrast dye injection. In our prospective study, we investigate parafoveal and peripapillary microvascular retinal networks in 18 MS patients (35 eyes) through angio-OCT (AngioVue, OptoVue). According to our results, early structural changes in MS patients without previous history of acute ON episode are unable to be detected. As a follow-up imaging technique, OCT is very useful for changes in axonal thickness and defines the progression rate of the dise...

Visual field simulation using optical coherence tomography and optical coherence tomographic angiography

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Disclosed herein are methods for simulating the results of a visual field (VF) test using an optical coherence tomography (OCT) system. The disclosed methods may utilize structural information extracted from OCT image datasets, such as thickness measurements, or may utilize functional information, such as blood perfusion measurements, extracted from OCT angiography (OCTA) image datasets. Other embodiments may be described and claimed. ( Read Full Article )

Optical coherence tomography angiography findings in patients with chronic thromboembolic pulmonary hypertension

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Purpose: To investigate microvascular changes in the retina and choroid of chronic thromboembolic pulmonary hypertension (CTEPH) patients in comparison to healthy controls. Methods: This observational clinical cohort study included 36 CTEPH patients (72 eyes) and 65 healthy controls (130 eyes). Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images were obtained from each participant using the AngioVue Imaging System (Optovue, Inc., Freemont, CA). Results: A number of differences were found in the CTEPH cohort, including reductions in mean vessel density (mVD) at the deep vascular complex of the macula and a reduction in mean subfoveal choroidal thickness (SFCT). Furthermore, the CTEPH group displayed an increase in foveal avascular zone (FAZ). The presence of at least one systemic disease, including arterial hypertension (HTN), diabetes (DM), chronic coronary syndrome (CCS) and/or hyperlipidaemia in CTEPH patients increased the range of vascul...

Glaucoma Diagnosis Through the Integration of Optical Coherence Tomography/Angiography and Machine Learning Diagnostic Models

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Glaucoma is the second leading cause of blindness worldwide.1 Primary open angle glaucoma (POAG), the most common variety, is defined as a progressive neurodegenerative disease of the retinal ganglion cells with characteristic features of the optic disc, usually accompanied by corresponding visual field (VF) defects, with or without elevated intraocular pressure (IOP).2 Although the exact etiology is still poorly understood, the most prevalent theories pertain to elevated IOP (mechanical), inherent poor blood flow to the optic nerve (vascular), or a combination of both.3 Multifactorial risk factors for glaucoma include increasing age, elevated IOP, Black race, family history ... ( Read Full Article )

Deep learning for quality assessment of optical coherence tomography angiography images

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Optical coherence tomography angiography (OCTA) is an emerging non-invasive technique for imaging the retinal vasculature. While there are many promising clinical applications for OCTA, determination of image quality remains a challenge. We developed a deep learning-based system using a ResNet152 neural network classifier, pretrained using ImageNet, to classify images of the superficial capillary plexus in 347 scans from 134 patients. Images were also manually graded by two independent graders as a ground truth for the supervised learning models. Because requirements for image quality may vary depending on the clinical or research setting, two models were trained—one to identify high-quality images and one to identify low-quality images. Our neural network models demonstrated outstanding area under the curve (AUC) metrics for both low quality image identification (AUC = 0.99, 95%CI 0.98–1.00, ( Read Full Article )

The Effect of Topical Brimonidine on the Ocular Hemodynamics in Patients of POAG Using OCTA

Topical Brimonidine is a well-established topical antigalucoma, ocular hypotensive therapeutic that has been in use since 1996. Brimonidine stands out among other topical ocular hypotensives in that it has a neuroprotective effect that is independent of IOP reduction. This has been demonstrated in multiple animal and human controlled studies both in vivo and in vitro. The mechanisms proposed so far to account for this neuroprotection focus mainly on molecular level antiapoptotic effects and modulation of some excitatory stimuli like glutamate. In this study we try to test the hypothesis that a positive hemodynamic profile of Brimonidine on ocular blood flow may be responsible at least in part for its unique neuroprotective effects. ( Read Full Article )

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