1. Articles in category: Ophthalmology

    49-72 of 13767 « 1 2 3 4 5 6 ... 572 573 574 »
    1. Medical College of Wisconsin Receives NIH Grant for Assessing Photoreceptor Structure and Function in Normal and Diseased Retinae

      Medical College of Wisconsin Receives NIH Grant for Assessing Photoreceptor Structure and Function in Normal and Diseased Retinae

      Medical College of Wisconsin Receives a 2020 NIH Grant for $486,444 for Assessing Photoreceptor Structure and Function in Normal and Diseased Retinae. The principal investigator is Joseph Carroll. Below is a summary of the proposed work. Inherited retinal degenerations affect approximately 1 in 1,500 individuals in the US, and given the extreme genotypic and phenotypic heterogeneity, the prospect of treating these devastating diseases is a formidable task. Nevertheless, trials examining novel therapeutic strategies are underway. An important key to success in the early phases of such trials is selection of patients with reasonable therapeutic potential – for example, a ...

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    2. Geometric Perfusion Deficits: A Novel OCT Angiography Biomarker for Diabetic Retinopathy Based on Oxygen Diffusion

      Geometric Perfusion Deficits: A Novel OCT Angiography Biomarker for Diabetic Retinopathy Based on Oxygen Diffusion

      Purpose To develop geometric perfusion deficits (GPD), an optical coherence tomography angiography (OCTA) biomarker based on oxygen diffusion, and to evaluate its utility in a pilot study of healthy subjects and patients with diabetic retinopathy (DR). Design Retrospective cross-sectional study. Methods Commercial spectral-domain OCTA instruments were used to acquire repeated 3×3 mm 2 and 6×6 mm 2 motion-corrected macular OCTA volumes. En face OCTA images corresponding to the superficial capillary plexus (SCP), deep capillary plexus (DCP), and full retinal projections were obtained using automatic segmentation. For each projection, the GPD percentage and the vessel density percentage, the control ...

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    3. Validity and reliability of semiautomatic ocular cycloposition measurement with Spectralis optical coherence tomography.

      Validity and reliability of semiautomatic ocular cycloposition measurement with Spectralis optical coherence tomography.

      PURPOSE Disc-fovea angle quantification in fundus photography (P-DFA) is considered the gold standard for cycloposition assessment. The FoDi software of the SD-OCT Spectralis also measures the DFA (O-DFA) based on subject fixation and offers important clinical advantages. This study aimed to analyze the validity and reliability of OCT measuring cycloposition and to determine its performance in eyes with poor foveal definition. DESIGN Validity and reliability analysis. METHODS In 60 eyes with normal foveal definition and 32 eyes with poorly defined fovea, ocular cycloposition was assessed by two observers with five fundus photographs and five FoDi analyses each. The patients were ...

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    4. Ophthalmological imaging device

      Ophthalmological imaging device

      An ophthalmological imaging device comprising an objective lens, an interference optical system, an image forming unit, an optical member, and an analyzer. The interference optical system divides light from a light source into measurement light and reference light, causes the measurement light to become incident on a subject's eye via the objective lens, and detects interference light between the reference light and return light of the measurement light that has exited from the subject's eye and passed through the objective lens. The image forming unit forms an image of the subject's eye based on a detection result ...

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    5. In vivo SS-OCT imaging of crystalline lens sutures

      In vivo SS-OCT imaging of crystalline lens sutures

      We demonstrate in vivo three-dimensional (3-D) visualization of crystalline lens sutures in healthy eyes using swept source optical coherence tomography (SS-OCT). Volumetric data sets of the crystalline lenses were acquired and processed to obtain enhanced contrast projection images and to extract suture patterns in both anterior and posterior lens. The results presented different types of the sutures including Y-sutures, simple and complex star sutures. Age-related changes in suture arrangement were characterized quantitatively. Crystalline lens suture imaging with SS-OCT might be a useful tool in fundamental studies on development and ageing of human lens.

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    6. In vivo Imaging of Reis–Bücklers and Thiel–Behnke Corneal Dystrophies Using Anterior Segment Optical Coherence Tomography

      In vivo Imaging of Reis–Bücklers and Thiel–Behnke Corneal Dystrophies Using Anterior Segment Optical Coherence Tomography

      Purpose: To investigate in vivo corneal changes of genetically confirmed Reis–Bücklers corneal dystrophy (RBCD) and Thiel–Behnke corneal dystrophy (TBCD) using anterior segment optical coherence tomography (AS-OCT). Design: A single-center, prospective, comparative case series. Methods: Seven patients from 3 pedigrees (3 males, 4 females) with RBCD [Arg124Leu (R124L) heterozygous missense mutation of human transforming growth factor beta-induced ( TGFBI ) gene] and 4 patients from 3 pedigrees (3 males, 1 female) with TBCD [Arg555Gln (R555Q) heterozygous missense mutation of TGFBI gene] were examined. Six patients with RBCD and three patients with TBCD exhibited recurrence after corneal surgery including penetrating keratoplasty ...

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    7. Swept-source optical coherence tomography angiography findings in choroidal and retinal tumors

      Swept-source optical coherence tomography angiography findings in choroidal and retinal tumors

      Objectives To report the swept-source optical coherence tomography angiography (SS-OCTA) findings in choroidal and retinal tumors. Methods A retrospective noncomparative interventional case series of 60 eyes having various choroidal and retinal tumors imaged with SS-OCTA (Topcon DR1 Triton Plus, Tokyo, Japan) between September 2018 and February 2020 was conducted. Inclusion criteria were tumor thickness <4 mm, tumor base diameter <10 mm, and tumor location at the posterior pole. Results Choroidal nevi usually demonstrated well-defined borders, hyperreflective internal structure, and no outer retinal involvement on SS-OCTA. Choroidal melanoma, in contrast to nevi, usually had ill-defined borders ( p  = 0.018), mixed hyperreflective ...

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    8. Impact of Pupil Dilation on Optical Coherence Tomography Angiography Retinal Microvasculature in Healthy Eyes

      Impact of Pupil Dilation on Optical Coherence Tomography Angiography Retinal Microvasculature in Healthy Eyes

      Précis: Small but significant decreases in OCTA-measured circumpapillary capillary density were observed in healthy eyes dilated with 2.5% phenylephrine/0.5% tropicamide. Though likely clinically insignificant, ophthalmologists should consider these changes when interpreting OCTA results from dilated eyes. Purpose: To investigate the effect of pupil dilation using 2.5% phenylephrine and 0.5% tropicamide on quantitative assessment of retinal microvasculature using OCTA. Methods: OptoVue AngioVue high density (HD) and non-HD OCTA macula and optic nerve head (ONH) images were obtained at 15-minute intervals pre- and post- dilation in 26 healthy participants (mean age: 40.0; 95% CI=33 ...

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    9. Iridocorneal Angle Assessment After Laser Iridotomy with Swept-source Optical Coherence Tomography

      Iridocorneal Angle Assessment After Laser Iridotomy with Swept-source Optical Coherence Tomography

      Aim: To investigate the reliability of anterior chamber angle (ACA) measurements in narrow angles and assess the effect of laser peripheral iridotomy (LPI) on these measurements using novel swept-source optical coherence tomography (SS-OCT) technology. Methods: In this prospective observational study, patients with gonioscopically narrow angles were enrolled and scheduled for prophylactic LPI. Twelve ACA sections were obtained in each eye using SS-OCT (ANTERION, Heidelberg Engineering, Germany) before and after Nd:YAG LPI. A built-in algorithm calculated ACA measurements after manual identification of the scleral spur and ACA recess. Eight ACA parameters were evaluated: ACA (ACA 500, ACA 750); Scleral Spur ...

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    10. Presumed activated retinal astrocytes and Müller cells in healthy and glaucomatous eyes detected by spectral domain optical coherence tomography

      Presumed activated retinal astrocytes and Müller cells in healthy and glaucomatous eyes detected by spectral domain optical coherence tomography

      Purpose To investigate presumed activated retinal astrocytes and Müller cells (ARAM) detected by scanning laser ophthalmoscopy (SLO) and spectral domain optical coherence tomography, and to investigate its presence in healthy controls as well as its relationship to posterior vitreal detachment (PVD) and glaucoma. Methods This retrospective study involved 1337 eyes of 805 controls between ages 8 and 90, and 250 eyes of 146 patients with glaucoma between the ages of 28 and 95. Subjects were counted as possessing ARAM only if they met the following criteria: (1) a patchy, discrete, glittering appearance on SLO, (2) a distinct, flat, hyper ...

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    11. Quantitative Optical Coherence Tomography Angiography Parameters in Type 1 Macular Neovascularization Secondary to Age-Related Macular Degeneration

      Quantitative Optical Coherence Tomography Angiography Parameters in Type 1 Macular Neovascularization Secondary to Age-Related Macular Degeneration

      Purpose : The purpose of this paper was to study type 1 macular neovascularization (MNV) quantitative optical coherence tomography (OCT) angiography (OCTA) features by means of advanced postprocessing analyses. Methods : We recruited patients affected by naïve type 1 MNV secondary to age-related macular degeneration (AMD) and age-matched controls. All patients underwent ophthalmologic examination and multimodal imaging. They were treated with pro-re-nata anti-VEGF injections. The ensuing follow-up lasted 24 months. Quantitative OCT and OCTA parameters were statistically analyzed to obtain cutoff values able to distinguish two clinically different patient subgroups. Main outcome measures were best-corrected visual acuity (BCVA), central macular thickness ...

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    12. Denoising Performance Evaluation of Automated Age-related Macular Degeneration Detection on Optical Coherence Tomography Images

      Denoising Performance Evaluation of Automated Age-related Macular Degeneration Detection on Optical Coherence Tomography Images

      Automated detection of eye diseases using artificial intelligence techniques on optical coherence tomography (OCT) images is widely researched in the field of ophthalmology. Such detections are usually performed with the aid of computers. Using high-level simulations, this study investigates and evaluates three automated age-related macular degeneration (AMD) detection flows in terms of computation time and detection accuracy for future hardware-accelerated designs of intelligent and portable OCT systems. In this study, a block-matching and 3-Dimension filter (BM3DF), a hybrid median filter (HMF), and an adaptive wiener filter (AWF) are used to denoise the OCT images. Support vector machine (SVM), AlexNet, GoogLeNet ...

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    13. High Resolution Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Visualization of Choroidal Vascular Occlusion

      High Resolution Multimodal Photoacoustic Microscopy and Optical Coherence Tomography Visualization of Choroidal Vascular Occlusion

      Photoacoustic microscopy is a novel, non-ionizing, non-invasive imaging technology that evaluates tissue absorption of short-pulsed light through the sound waves emitted by the tissue and has numerous biomedical applications. In this study, a custom-built multimodal imaging system, including photoacoustic microscopy (PAM) and optical coherence tomography (OCT), has been developed to evaluate choroidal vascular occlusion (CVO). CVO was performed on three living rabbits using laser photocoagulation. Longitudinal imaging of CVO was obtained using multiple imaging tools such as color fundus photography, fluorescein angiography, indocyanine green angiography (ICGA), OCT, and PAM. PAM images were acquired at different wavelengths, ranging from 532 to ...

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    14. Repeatability, reproducibility, and comparison of ocular biometry using a new optical coherence tomography-based system and another device

      Repeatability, reproducibility, and comparison of ocular biometry using a new optical coherence tomography-based system and another device

      Precise measurement of axial length before cataract surgery is necessary for the proper lens implantation. We included 100 eyes of 56 patients in the study. The mean age was 41 (15–84 years). Measurements of axial length, anterior chamber depth (ACD) carried out with the new Revo NX were compared with those obtained with the IOLMaster 500. Interoperator testing was performed on 56 eyes of 56 participants. To test repeatability, axial length, ACD, central corneal thickness, and lens thickness were used. Inter-operator reproducibility was also assessed. The results were evaluated using Bland–Altman analyses. The mean ACD measured with the ...

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    15. Repeatability and reproducibility of post-mortem central corneal thickness measurements using a portable optical coherence tomography system in humans: a prospective multicenter study

      Repeatability and reproducibility of post-mortem central corneal thickness measurements using a portable optical coherence tomography system in humans: a prospective multicenter study

      To assess the repeatability and reproducibility of post-mortem central corneal thickness (CCT) measurements made by the portable iVue spectra-domain (SD) optical coherence tomography OCT (Optovue Inc, Fremont, CA) system in humans, and to prospectively establish the time-course of CCT after death. In a prospective multicenter setting, CCT measurements were obtained from 58 human eyes at the following 16 time-points after death: immediately (within 2 h), and at each hour by the next 17 h. The range of CCT values for each subject was determined and longitudinal data were used to illustrate the variation in open and close eye mode. All ...

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      Mentions: Optovue
    16. Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices

      Intradevice Repeatability and Interdevice Agreement of Ocular Biometric Measurements: A Comparison of Two Swept-Source Anterior Segment OCT Devices

      Purpose : To assess the repeatability and agreement of ocular biometric parameters measured using the Tomey CASIA SS-1000 and Heidelberg ANTERION anterior segment optical coherence tomography (AS-OCT) devices. Methods : Both eyes of subjects 18 years of age or older were scanned three times with the CASIA and ANTERION under standardized dark lighting. One AS-OCT image along the horizontal (temporal-nasal) meridian was analyzed per eye and per scan. Pupillary diameter (PD) was within 15% for all pairwise comparisons. Anterior chamber depth, lens vault, anterior chamber width, angle opening distance, trabecular iris space area, and scleral spur angle (SSA500) were measured using manufacturer-provided ...

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    17. Optical coherence tomography angiography and multifocal electroretinogram findings in paracentral acute middle maculopathy

      Optical coherence tomography angiography and multifocal electroretinogram findings in paracentral acute middle maculopathy

      Paracentral acute middle maculopathy (PAMM) is an optical coherence tomography (OCT) finding seen in patients with retinal capillary ischemia. In this case report, we present a case of PAMM after a transient central retinal artery occlusion and the multifocal electroretinogram (mfERG) and other multimodal imaging findings. Clinical examination, OCT angiography, OCT en face, fluorescein angiography, and visual fields were performed at the baseline and follow-up examinations. As a result, we identified in this PAMM case evidence of hypoperfusion in both the choriocapillaris as well as the deep capillary plexus. To the best of our knowledge, the involvement of choriocapillaris has ...

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    18. Different follow-up OCT analyses of traumatic optic neuropathy. A case report

      Different follow-up OCT analyses of traumatic optic neuropathy. A case report

      Purpose Optical coherence tomography (OCT) is established as a promising technology for assessing the optic nerve atrophy progression after trauma. However, reports on the effectiveness and sensitivity of ganglion cell layer (GCL) and Bruch's membrane opening-minimum rim width (BMO-MRW) for studying this damage course over time are still lacking. Observations A 53-year-old man with severe optic nerve trauma had repeated OCT scans of the retinal nerve fiber layer (RNFL), GCL and BMO-MRW during 12 months after the injury. There was gradual damage in all measurements. Interestingly, BMO-MRW was the first analysis affected whilst GCL showed the greatest damage over ...

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    19. Use of the new MultiColour SPECTRALIS® software for identifying retinal nerve fibre layer defects

      Use of the new MultiColour SPECTRALIS® software for identifying retinal nerve fibre layer defects

      The classical fibre photography traditionally used to identify defects in the retinal nerve fibre layer (RNFL), has been partially discontinued due to poor availability. The new MultiColour module of SPECTRALIS® Optical Coherence Tomography (OCT), using three different laser wavelengths simultaneously, can provide images that identify the structures of the retina in different colours according to their depth. A small concordance study was conducted to determine the usefulness of the new MultiColour software versus traditional fibre photography in identifying RNFL defects. The inter-observer agreement in the interpretation of MultiColour images was good (κ=.746; P <.001), as by using Multicolour they were ...

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    20. Optical coherence tomography angiography in diabetes: focus on microaneurysms

      Optical coherence tomography angiography in diabetes: focus on microaneurysms

      The introduction of optical coherence tomography angiography (OCTA) has remarkably expanded our knowledge of the ocular vascular alterations occurring in diabetes. In this article, a review of the prominent OCTA findings in diabetes is followed by a description of salient histological and anatomical features of microaneurysms, essential for the proper interpretation of in vivo imaging of these retinal vascular abnormalities. The recent employment of a three-dimensional (3D) visualization in OCTA imaging is also discussed. The latter imaging technique has granted a detailed characterization of microaneurysms in vivo.

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    21. Aqueous Cytokine Expression and Higher-Order OCT Biomarkers: Assessment of the Anatomic-Biologic Bridge in the Imagine Dme Study

      Aqueous Cytokine Expression and Higher-Order OCT Biomarkers: Assessment of the Anatomic-Biologic Bridge in the Imagine Dme Study

      Purpose To identify biomarkers for predicting response to anti-VEGF therapy in diabetic macular edema (DME) and evaluate any links between cytokine expression and OCT phenotype. Design IMAGINE DME is a post-hoc image analysis and cytokine expression assessment of the DAVE randomized clinical trial. Methods Subjects were categorized as anatomical Responders or Nonresponders,and within the Responder group as Rebounders and Nonrebounders based on quantitative, longitudinal optical coherence tomography (OCT) criteria. Retinal layer and fluid features were extracted using an OCT machine-learning augmented segmentation platform. Responders were further sub-classified by rapidity of response. Aqueous concentrations of 54 cytokines at multiple timepoints ...

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    22. Analysis of the Vascular Morphology of the Fibrotic Choroidal Neovascularization in Neovascular Age-Related Macular Degeneration Using Optical Coherence Tomography Angiography

      Analysis of the Vascular Morphology of the Fibrotic Choroidal Neovascularization in Neovascular Age-Related Macular Degeneration Using Optical Coherence Tomography Angiography

      Purpose Choroidal neovascularization (CNV) in neovascular age-related macular degeneration (nAMD) undergoing anti-VEGF therapy transforms into a fibrotic lesion. This fibrovascular transformation is associated with a great variety of functional and morphological effects. The aim of this study was to investigate the vascular morphology of fibrotic CNV, to compare it with its surrounding tissue and to identify phenotypes using optical coherence tomography angiography (OCTA). Methods In 18 eyes with fibrotic CNV in nAMD spectral domain OCT (SD-OCT) and OCTA were performed. The automated segmentation lines were manually adjusted. A slab from 60 µm beneath Bruchʼs membrane to the inner edge of ...

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    23. Patterns of Retinal Ganglion Cell Damage in Nonarteritic Anterior Ischemic Optic Neuropathy Assessed by Swept-Source Optical Coherence Tomography

      Patterns of Retinal Ganglion Cell Damage in Nonarteritic Anterior Ischemic Optic Neuropathy Assessed by Swept-Source Optical Coherence Tomography

      Objective: To evaluate the ability of macular ganglion cell and inner plexiform layer (mGCIPL) and retinal nerve fiber layer (RNFL) thickness measurements by long-wavelength swept-source optical coherence tomography (SS-OCT) to assess retinal ganglion cell (RGC) damage in nonarteritic anterior ischemic optic neuropathy (NAION). Methods: A retrospective study of 20 patients with unilateral NAION was performed. SS-OCT scanning of the macular and peripapillary areas was performed to measure the total and six-sector thicknesses of macular RNFL (mRNFL) and mGCIPL, as well as peripapillary RNFL (pRNFL) thicknesses in global and 12 clock-hour sectors. Further comparison of these thicknesses between NAION involved eyes ...

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