1. Articles in category: Ophthalmology

    73-96 of 15537 « 1 2 3 4 5 6 7 ... 646 647 648 »
    1. Current Developments in Corneal Topography and Tomography

      Current Developments in Corneal Topography and Tomography

      Introduction: Accurate assessment of the corneal shape is important in cataract and refractive surgery, both in screening of candidates as well as for analyzing postoperative outcomes. Although corneal topography and tomography are widely used, it is common that these technologies are confused. The aim of this study was to present the current developments of these technologies and particularly distinguish between corneal topography and tomography. Methods: The PubMed, Web of Science and Embase databases were the main resources used to investigate the medical literature. The following keywords were used in various combinations: cornea, corneal, topography, tomography, Scheimpflug, Pentacam, optical coherence tomography ...

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    2. Computer-Aided Detection (CADe) System with Optical Coherent Tomography for Melanin Morphology Quantification in Melasma Patients

      Computer-Aided Detection (CADe) System with Optical Coherent Tomography for Melanin Morphology Quantification in Melasma Patients

      Dark skin-type individuals have a greater tendency to have pigmentary disorders, among which melasma is especially refractory to treat and often recurs. Objective measurement of melanin amount helps evaluate the treatment response of pigmentary disorders. However, naked-eye evaluation is subjective to weariness and bias. We used a cellular resolution full-field optical coherence tomography (FF-OCT) to assess melanin features of melasma lesions and perilesional skin on the cheeks of eight Asian patients. A computer-aided detection (CADe) system is proposed to mark and quantify melanin. This system combines spatial compounding-based denoising convolutional neural networks (SC-DnCNN), and through image processing techniques, various types ...

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    3. Automatic Diagnosis of Bipolar Disorder Using Optical Coherence Tomography Data and Artificial Intelligence

      Automatic Diagnosis of Bipolar Disorder Using Optical Coherence Tomography Data and Artificial Intelligence

      Background: The aim of this study is to explore an objective approach that aids the diagnosis of bipolar disorder (BD), based on optical coherence tomography (OCT) data which are analyzed using artificial intelligence. Methods: Structural analyses of nine layers of the retina were analyzed in 17 type I BD patients and 42 controls, according to the areas defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. The most discriminating variables made up the feature vector of several automatic classifiers: Gaussian Naive Bayes, K-nearest neighbors and support vector machines. Results: BD patients presented retinal thinning affecting most layers, compared to ...

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    4. Normative intercapillary distance and vessel density data in the temporal retina assessed by wide-field spectral-domain optical coherence tomography angiography

      Normative intercapillary distance and vessel density data in the temporal retina assessed by wide-field spectral-domain optical coherence tomography angiography

      A limitation of conventional optical coherence tomography angiography (OCTA) is the limited field of view normally used in data acquisition. As the technology improves, larger fields of view that capture information away from the macular are being explored in order to provide an enhanced ability to detect pathology. However, normative measurements for important OCTA metrics like vessel density and intercapillary distance are not currently well-characterized in the peripheral retina. In this prospective study, we measured vessel density and intercapillary distance of the superficial vascular complex, ganglion cell layer plexus, and deep capillary plexus in montaged macular/temporal scans from 53 ...

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    5. Characterizing right-angled vessel in macular telangiectasia type 2 with structural optical coherence tomography

      Characterizing right-angled vessel in macular telangiectasia type 2 with structural optical coherence tomography

      We investigated the structural findings on spectral-domain optical coherence tomography (SD-OCT) related to the presence of right-angled vessels (RAV) in patients with macular telangiectasia (MacTel) type 2 with severity 3 in Korea. A retrospective multicenter cross-sectional study was conducted in six tertiary hospitals in Korea; the study included 116 MacTel type 2 eyes with severity 3. The SD-OCT findings were compared between eyes with RAV on fundus photography or fluorescein angiography and those without RAV. Logistic regression was performed to determine factors associated with the presence of RAV. Fifty eyes presented with RAV and 61 eyes without RAV. More eyes ...

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    6. A multi-task deep-learning system for assessment of diabetic macular ischemia on optical coherence tomography angiography images

      A multi-task deep-learning system for assessment of diabetic macular ischemia on optical coherence tomography angiography images

      Purpose: We aimed to develop and test a deep-learning (DL) system to perform image quality and diabetic macular ischemia (DMI) assessment on OCTA images. Methods: This study included 7,194 OCTA images with diabetes mellitus for training and primary validation, and 960 images from three independent datasets for external testing. A trinary classification for image quality assessment and presence or absence of DMI for DMI assessment were labelled on all OCTA images. Two DenseNet-161 models were built for both tasks for OCTA images of superficial and deep capillary plexus, respectively. External testing was performed on three unseen datasets in which ...

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    7. Five dimensions of age-related macular degeneration provide new insight

      Five dimensions of age-related macular degeneration provide new insight

      A new study — published in Investigative Ophthalmology and Visual Science from University of Alabama at Birmingham researchers — suggests that linking to a fifth dimension for molecules and affected cells could help define new therapeutic strategies for those suffering from age-related macular degeneration. Christine A. Curcio, Ph.D., White-McKee Endowed Professor in Ophthalmology with UAB’s Department of Ophthalmology and Visual Sciences , says these findings could open new possibilities for patients with AMD. “The retina is like the camera chip in a smartphone — it takes pictures for the brain,” she said. “Each light-sensitive photoreceptor sits in a precise location (x,y ...

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    8. Central macular OCTA parameters in glaucoma

      Central macular OCTA parameters in glaucoma

      Background/aims: To investigate the relationship between the foveal avascular zone (FAZ) parameters assessed by optical coherence tomography angiography (OCTA) and central visual field parameters in glaucoma and healthy subjects. Methods: One hundred and eighty-eight subjects (248 eyes), including 24 healthy (38 eyes), 37 glaucoma suspect (42 eyes, and 127 primary open angle glaucoma (POAG) patients (168 eyes), underwent imaging using OCTA and standard automated perimetry using the 24-2 and 10-2 Swedish Interactive Thresholding Algorithm. OCTA-based and OCT-based FAZ parameters (superficial FAZ area, FAZ circumference), foveal vessel density (FD300) and foveal thickness were measured. The correlation between FAZ parameters and ...

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      Mentions: UCSD
    9. Comparison of multicolor scanning laser ophthalmoscopy and optical coherence tomography angiography for detection of microaneurysms in diabetic retinopathy

      Comparison of multicolor scanning laser ophthalmoscopy and optical coherence tomography angiography for detection of microaneurysms in diabetic retinopathy

      This study aimed to evaluate the usefulness of multicolor (MC) scanning laser ophthalmoscopy (MC-SLO) in detecting microaneurysm (MA) in eyes with diabetic retinopathy (DR). This was a retrospective cross-sectional study. Eyes with DR underwent fluorescein angiography (FA), MC-SLO, optical coherence tomography angiography (OCTA), and color fundus photography (CFP) were analyzed. The foveal region was cut in an 6 × 6 mm image and the number of MA in each image was counted by retina specialists to determine the sensitivity and positive predictive value. FA results were used as the ground standard. MAs were classified as those with early, late, or no ...

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    10. Assessment of the pigeon (Columba livia) retina with spectral domain optical coherence tomography

      Assessment of the pigeon (Columba livia) retina with spectral domain optical coherence tomography

      Background: To assess the normal retina of the pigeon eye using spectral domain optical coherence tomography (SD-OCT) and establish a normative reference. Methods: Twelve eyes of six ophthalmologically normal pigeons ( Columba livia ) were included. SD-OCT images were taken with dilated pupils under sedation. Four meridians, including the fovea, optic disc, red field, and yellow field, were obtained in each eye. The layers, including full thickness (FT), ganglion cell complex (GCC), thickness from the retinal pigmented epithelium to the outer nuclear layer (RPE-ONL), and from the retinal pigmented epithelium to the inner nuclear layer (RPE-INL), were manually measured. Results: The average ...

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    11. Automated delineation of corneal layers on OCT images using a boundary-guided CNN

      Automated delineation of corneal layers on OCT images using a boundary-guided CNN

      Accurate segmentation of corneal layers depicted on optical coherence tomography (OCT) images is very helpful for quantitatively assessing and diagnosing corneal diseases ( e.g ., keratoconus and dry eye). In this study, we presented a novel boundary-guided convolutional neural network (CNN) architecture (BG-CNN) to simultaneously extract different corneal layers and delineate their boundaries. The developed BG-CNN architecture used three convolutional blocks to construct two network modules on the basis of the classical U-Net network. We trained and validated the network on a dataset consisting of 1,712 OCT images acquired on 121 subjects using a 10-fold cross-validation method. Our experiments showed ...

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    12. Optical Coherence Tomography and Visual Evoked Potentials as Prognostic and Monitoring Tools in Progressive Multiple Sclerosis

      Optical Coherence Tomography and Visual Evoked Potentials as Prognostic and Monitoring Tools in Progressive Multiple Sclerosis

      Understanding the mechanisms underlying progression and developing new treatments for progressive multiple sclerosis (PMS) are among the major challenges in the field of central nervous system (CNS) demyelinating diseases. Over the last 10 years, also because of some technological advances, the visual pathways have emerged as a useful platform to study the processes of demyelination/remyelination and their relationship with axonal degeneration/protection. The wider availability and technological advances in optical coherence tomography (OCT) have allowed to add information on structural neuroretinal changes, in addition to functional information provided by visual evoked potentials (VEPs). The present review will address the ...

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    13. Semi-supervised generative adversarial networks for closed-angle detection on anterior segment optical coherence tomography images: an empirical study with a small training dataset

      Semi-supervised generative adversarial networks for closed-angle detection on anterior segment optical coherence tomography images: an empirical study with a small training dataset

      Background: Semi-supervised learning algorithms can leverage an unlabeled dataset when labeling is limited or expensive to obtain. In the current study, we developed and evaluated a semi-supervised generative adversarial networks (GANs) model that detects closed-angle on anterior segment optical coherence tomography (AS-OCT) images using a small labeled dataset. Methods: In this cross-sectional study, a semi-supervised GANs model was developed for automatic closed-angle detection training on a small labeled and large unsupervised training dataset collected from the Joint Shantou International Eye Center of Shantou University and the Chinese University of Hong Kong (JSIEC). The closed-angle was defined as iris-trabecular contact beyond ...

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    14. Evaluation of macular microvasculature and foveal avascular zone in patients with retinal vein occlusion using optical coherence tomography angiography

      Evaluation of macular microvasculature and foveal avascular zone in patients with retinal vein occlusion using optical coherence tomography angiography

      Purposes: To quantitatively evaluate the vessel density of macular microvasculature, choriocapillary, and foveal avascular zone (FAZ) in both eyes of patients with unilateral retinal vein occlusion (RVO) using the optical coherence tomography angiography (OCTA) compared with the normal controls. Methods: A retrospective review was conducted on 72 patients with unilateral RVO (72 eyes with RVO and 72 RVO fellow eyes) and 72 healthy individuals (72 normal control eyes). The 3 × 3 mm macular angiogram was acquired using the OCTA. The vessel densities of the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillary plexus (CCP) were measured, and ...

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    15. Refractive Prediction Error in Cataract Surgery Using an Optical Biometer Equipped with Anterior-Segment Optical Coherence Tomography

      Refractive Prediction Error in Cataract Surgery Using an Optical Biometer Equipped with Anterior-Segment Optical Coherence Tomography

      Purpose: To evaluate refractive error after cataract surgery using an optical biometer equipped with anterior-segment optical coherence tomography (AS-OCT). Setting: Chukyo Eye Clinic, Nagoya, Japan. Design: Retrospective observational design. Methods: In total, 150 patients with cataract (150 eyes, mean age 73.4 ± 8.2 years, men 76, women 74), who underwent measurement of parameters with the anterior-segment OCT scanners ANTERIONTM (AS-OCTB) and IOL Master 700 (OCTB) before cataract surgery, were enrolled in the study. Refractive prediction error was compared between the two devices using the SRK/T, Haigis, and Barrett UII formulas for IOL power calculation. Results: There were significant ...

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    16. Agreement of IOL power calculation between IOLMaster 700 and Anterion swept source optical coherence tomography-based biometers

      Agreement of IOL power calculation between IOLMaster 700 and Anterion swept source optical coherence tomography-based biometers

      Purpose: To assess agreement of measurements by two swept source optical coherence tomography (SS-OCT) biometers and to evaluate the prediction error (PE) in intraocular lens (IOL) power calculation with seven formulas. Setting: Tertiary public eye hospital. Design: Consecutive observational. Methods: Axial length (AL), keratometry (K), anterior chamber depth (ACD), lens thickness (LT), and corneal diameter (CD) were measured with IOL Master 700 (Biometer A) and Anterion (Biometer B). Agreement was quantified by the limits of agreement (LoAs) and concordance correlation coefficient (CCC). The PE, the median absolute error (MedAE), and the mean absolute error (MAE) of the Barrett Universal II ...

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    17. Detection of early stage alzheimer's disease and mild cognitive impairment

      Detection of early stage alzheimer's disease and mild cognitive impairment

      Systems and methods are described herein for determining that a patient has indications mild cognitive impairment (MCI) or early stage Alzheimer's disease (AD). Microperimetry is used to assess the functional integrity of the patient's retina. Optical Coherence Tomography is used to assess the structural integrity of the patient's retina. Reductions in the size and function of the patient's retina indicate that the patient may have MCI or early stage AD.

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    18. Optical Coherence Tomography Angiography in Type 1 Diabetes Mellitus. Report 4: Glycated Haemoglobin

      Optical Coherence Tomography Angiography in Type 1 Diabetes Mellitus. Report 4: Glycated Haemoglobin

      The purpose of this study was to evaluate specifically the relationship between glycated haemoglobin (HbA1c) levels and retinal optical coherence tomography (OCT) and OCT angiography (OCTA) parameters in type 1 Diabetes Mellitus (DM). A total of 478 type 1 DM patients and 115 controls were included in a prospective OCTA trial (ClinicalTrials.gov NCT03422965). Subgroup analysis was performed for controls, no diabetic retinopathy (DM-no DR) and DR patients (DM-DR), and HbA1c levels. OCT and OCTA measurements were compared with HbA1c levels (current and previous 5 years). DM-no DR patients with HbA1c levels >7.5% showed lower VD than DM-DR and ...

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    19. Clinical Role of Swept Source Anterior Segment Optical Coherence Tomography in Strabismus Re-Operation with Lost Surgical Details

      Clinical Role of Swept Source Anterior Segment Optical Coherence Tomography in Strabismus Re-Operation with Lost Surgical Details

      Background: To characterize the diagnostic role of swept source anterior segment optical coherence tomography (SS-ASOCT) in strabismus re-operations with lost surgical details. Methods: Patients presenting to our outpatient services for strabismus care from February 2020 to March 15th 2021 were systematically evaluated. Those willing to undergo re-operation were included in the study. A total of 30 patients were identified and out of this a total of 10 eyes of 10 patients with lost surgical details were finally included in the study. Demographic details, preoperative deviation, ocular findings, orthoptic measurements, detailed SS-ASOCT findings, intraoperative measurements, and post-operative outcomes were recorded. Results ...

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    20. SD-OCT and FAF Biomarkers Help Quantify GA Progression

      SD-OCT and FAF Biomarkers Help Quantify GA Progression

      Two prognostic tools that may help guide management decisions for age-related macular degeneration (AMD) patients with geographic atrophy (GA) include spectral-domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF). A recent study examined several biomarkers for GA that can be measured through these imaging modalities to better inform treatment. One hundred patients with GA underwent both SD-OCT and FAF imaging throughout a combined total of 1,062 visits, with follow-up lasting one to three years. Using a deep learning algorithm, the researchers quantitatively assessed hyperreflective foci (HRF) in SD-OCT volumes, which have been proven to represent activated retinal pigment epithelium ...

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    21. The structure-function correlation analysed by OCT and full field ERG in typical and pericentral subtypes of retinitis pigmentosa

      The structure-function correlation analysed by OCT and full field ERG in typical and pericentral subtypes of retinitis pigmentosa

      To investigate the structure-function correlation analysed by full-field electroretinography (ffERG) and optical coherence tomography (OCT) in typical and pericentral subtypes of retinitis pigmentosa (RP). A retrospective, cross-sectional, observational study of right eyes was conducted. The primary analysis used ffERG data to compare the RP subtypes. The subgroup analysis was used to correlate the structure, analysed by OCT, and function, determined by ffERG. Linear regressions explored the relationship between best-corrected visual acuity (BCVA) and multiple parameters. A total of 188 eyes were included. Amplitudes of responses of rod, rod-cone, cone, and 30 Hz flicker of typical type were lower than those ...

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    22. Circumpapillary OCT-focused hybrid learning for glaucoma grading using tailored prototypical neural networks

      Circumpapillary OCT-focused hybrid learning for glaucoma grading using tailored prototypical neural networks

      Glaucoma is one of the leading causes of blindness worldwide and Optical Coherence Tomography (OCT) is the quintessential imaging technique for its detection. Unlike most of the state-of-the-art studies focused on glaucoma detection, in this paper, we propose, for the first time, a novel framework for glaucoma grading using raw circumpapillary B-scans. In particular, we set out a new OCT-based hybrid network which combines hand-driven and deep learning algorithms. An OCT-specific descriptor is proposed to extract hand-crafted features related to the retinal nerve fibre layer (RNFL). In parallel, an innovative CNN is developed using skip-connections to include tailored residual and ...

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    23. OPTICAL COHERENCE TOMOGRAPHY FEATURES OF POLYPOIDAL LESION CLOSURE IN POLYPOIDAL CHOROIDAL VASCULOPATHY TREATED WITH AFLIBERCEPT

      OPTICAL COHERENCE TOMOGRAPHY FEATURES OF POLYPOIDAL LESION CLOSURE IN POLYPOIDAL CHOROIDAL VASCULOPATHY TREATED WITH AFLIBERCEPT

      Purpose: To evaluate whether optical coherence tomography (OCT) can determine polypoidal lesion (PL) perfusion in polypoidal choroidal vasculopathy (PCV) eyes following 12-months of aflibercept monotherapy. PL perfusion status, assessed by indocyanine green angiography (ICGA), is an important anatomical outcome in PCV management. Methods: Post-hoc data from a prospective randomised, open-label, study in eyes with PCV undergoing monotherapy with aflibercept evaluated PL perfusion status based on ICGA (gold standard) and OCT features from baseline to 12-months. Results: Individual PLs(110 in total) from 48 eyes(48 patients) showed at 12-months, 57/110 PLs(51.8%) were closed on ICGA. At 12-months ...

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