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Retinal image analysis

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https://www.readbyqxmd.com/read/28430181/supervised-learning-and-dimension-reduction-techniques-for-quantification-of-retinal-fluid-in-optical-coherence-tomography-images
#1
A Breger, M Ehler, H Bogunovic, S M Waldstein, A-M Philip, U Schmidt-Erfurth, B S Gerendas
PurposeThe purpose of the present study is to develop fast automated quantification of retinal fluid in optical coherence tomography (OCT) image sets.MethodsWe developed an image analysis pipeline tailored towards OCT images that consists of five steps for binary retinal fluid segmentation. The method is based on feature extraction, pre-segmention, dimension reduction procedures, and supervised learning tools.ResultsFluid identification using our pipeline was tested on two separate patient groups: one associated to neovascular age-related macular degeneration, the other showing diabetic macular edema...
April 21, 2017: Eye
https://www.readbyqxmd.com/read/28427063/optical-coherence-tomography-angiography-in-diabetic-maculopathy
#2
Gabriel Coscas, Marco Lupidi, Florence Coscas
Fluorescein angiography (FA) and indocyanine green angiography have provided information about the normal retinal and choroidal anatomy, nearly comparable to histological findings. These tests have been fundamental in the evaluation of all retinal and choroidal vascular diseases and have allowed clinicians to define and diagnose several pathological conditions. FA became the "gold standard" in retinal imaging due to the capacity to visualize the retinal capillary bed and its changes, both in the macular area and in the periphery...
2017: Developments in Ophthalmology
https://www.readbyqxmd.com/read/28426631/directional-changes-in-tissue-reflectivity-may-influence-flow-detection-on-optical-coherence-tomography-angiography
#3
Rosa Dolz-Marco, K Bailey Freund
PURPOSE: To determine if directional or anatomical changes in tissue reflectivity of Henle fiber layer (HFL) may influence flow detection on optical coherence tomography angiography (OCT-A). METHODS: Cross-sectional analysis of consecutive cases undergoing OCT-A. Directional changes in visualization of HFL were either produced manually by moving the beam entrance within the pupil or observed occurring naturally because of tilting of the OCT line-scan within a myopic staphyloma...
April 19, 2017: Retina
https://www.readbyqxmd.com/read/28422669/bioinspired-approach-to-modeling-retinal-ganglion-cells-using-system-identification-techniques
#4
Philip J Vance, Gautham P Das, Dermot Kerr, Sonya A Coleman, T Martin McGinnity, Tim Gollisch, Jian K Liu
The processing capabilities of biological vision systems are still vastly superior to artificial vision, even though this has been an active area of research for over half a century. Current artificial vision techniques integrate many insights from biology yet they remain far-off the capabilities of animals and humans in terms of speed, power, and performance. A key aspect to modeling the human visual system is the ability to accurately model the behavior and computation within the retina. In particular, we focus on modeling the retinal ganglion cells (RGCs) as they convey the accumulated data of real world images as action potentials onto the visual cortex via the optic nerve...
April 12, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28419396/correlation-between-mesopic-retinal-sensitivity-and-optical-coherence-tomographic-metrics-of-the-outer-retina-in-patients-with-non-atrophic-dry-age-related-macular-degeneration
#5
Tudor C Tepelus, Amir H Hariri, Mayss Al-Sheikh, SriniVas R Sadda
BACKGROUND AND OBJECTIVE: To determine the correlation between mesopic retinal sensitivity and optical coherence tomographic metrics of the outer retina in patients with intermediate age-related macular degeneration (AMD). PATIENTS AND METHODS: Participants with nonatrophic dry AMD underwent mesopic MP-3 microperimetry (Nidek, Padova, Italy) and both Nidek and Cirrus (Carl Zeiss Meditec, Dublin, CA) spectral-domain optical coherence tomography (SD-OCT). The volume of the outer retinal layers was measured on the Nidek SD-OCT scans using the automatic segmentation algorithm of Navis-EX software...
April 1, 2017: Ophthalmic Surgery, Lasers & Imaging Retina
https://www.readbyqxmd.com/read/28414059/a-mouse-ocular-explant-model-that-enables-the-study-of-living-optic-nerve-head-events-after-acute-and-chronic-intraocular-pressure-elevation-focusing-on-retinal-ganglion-cell-axons-and-mitochondria
#6
Elizabeth C Kimball, Mary E Pease, Matthew R Steinhart, Ericka N Oglesby, Ian Pitha, Cathy Nguyen, Harry A Quigley
We developed an explant model of the mouse eye and optic nerve that facilitates the study of retinal ganglion cell axons and mitochondria in the living optic nerve head (ONH) in an ex vivo environment. Two transgenic mouse strains were used, one expressing yellow fluorescent protein in selected axons and a second strain expressing cyan fluorescent protein in all mitochondria. We viewed an explanted mouse eye and optic nerve by laser scanning microscopy at and behind the ONH, the site of glaucoma injury. Explants from previously untreated mice were studied with the intraocular pressure (IOP) set artificially at normal or elevated levels for several hours...
April 14, 2017: Experimental Eye Research
https://www.readbyqxmd.com/read/28412069/whole-exome-sequencing-identifies-biallelic-idh3a-variants-as-a-cause-of-retinitis-pigmentosa-accompanied-by-pseudocoloboma
#7
Laurence H M Pierrache, Adva Kimchi, Rinki Ratnapriya, Lisa Roberts, Galuh D N Astuti, Alexey Obolensky, Avigail Beryozkin, Martha J H Tjon-Fo-Sang, Jose Schuil, Caroline C W Klaver, Ernie M H F Bongers, Lonneke Haer-Wigman, Nicoline Schalij, Martijn H Breuning, Gratia M Fischer, Eyal Banin, Raj S Ramesar, Anand Swaroop, L Ingeborgh van den Born, Dror Sharon, Frans P M Cremers
PURPOSE: To identify the genetic cause of and describe the phenotype in 4 families with autosomal recessive retinitis pigmentosa (arRP) that can be associated with pseudocoloboma. DESIGN: Case series. PARTICIPANTS: Seven patients from 4 unrelated families with arRP, among whom 3 patients had bilateral early-onset macular pseudocoloboma. METHODS: We performed homozygosity mapping and whole-exome sequencing in 5 probands and 2 unaffected family members from 4 unrelated families...
April 12, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28408038/temporal-relation-between-macular-ganglion-cell-inner-plexiform-layer-loss-and-peripapillary-retinal-nerve-fiber-layer-loss-in-glaucoma
#8
Young Kook Kim, Ahnul Ha, Kyeong Ik Na, Hae Jin Kim, Jin Wook Jeoung, Ki Ho Park
PURPOSE: To investigate the temporal relationship between inferior macular ganglion cell-inner plexiform layer (mGCIPL) loss and corresponding peripapillary retinal nerve fiber layer (pRNFL) defect on the optical coherence tomography (OCT) deviation map in glaucoma. DESIGN: Retrospective, observational study. PARTICIPANTS: A total of 151 patients with early-stage glaucoma (visual field [VF] mean deviation between -1.5 and -5.5 decibels [dB])...
April 10, 2017: Ophthalmology
https://www.readbyqxmd.com/read/28407012/relation-between-macular-morphology-and-treatment-frequency-during-twelve-months-with-ranibizumab-for-diabetic-macular-edema
#9
Yuki Mori, Tomoaki Murakami, Kiyoshi Suzuma, Kenji Ishihara, Shin Yoshitake, Masahiro Fujimoto, Yoko Dodo, Tatsuya Yoshitake, Yuko Miwa, Akitaka Tsujikawa
PURPOSE: To investigate whether baseline optical coherence tomography (OCT) parameters can predict the treatment frequency of intravitreal ranibizumab (IVR) injections during the first year in patients with diabetic macular edema (DME) treated with pro re nata (PRN) IVR injections. METHODS: We retrospectively reviewed 68 eyes of 63 patients with center-involved DME who received IVR injections for 12 months or longer according to three monthly IVR injections followed by the PRN dosing...
2017: PloS One
https://www.readbyqxmd.com/read/28406171/optical-coherence-tomography-angiography-to-estimate-retinal-blood-flow-in-eyes-with-retinitis-pigmentosa
#10
Masako Sugahara, Manabu Miyata, Kenji Ishihara, Norimoto Gotoh, Satoshi Morooka, Ken Ogino, Tomoko Hasegawa, Takako Hirashima, Munemitsu Yoshikawa, Masayuki Hata, Yuki Muraoka, Sotaro Ooto, Kenji Yamashiro, Nagahisa Yoshimura
Ophthalmologists sometimes face difficulties in identifying the origin of visual acuity (VA) loss in a retinitis pigmentosa (RP) patient, particularly before cataract surgery: cataract or the retinal disease state. Therefore, it is important to identify the significant factors correlating with VA. Nowadays, retinal blood flow in superficial and deep layers can be estimated non-invasively using optical coherence tomography angiography (OCTA). We estimated blood flow per retinal layer by using OCTA; investigated the correlation between VA and other parameters including blood flow and retinal thickness; and identified the most associated factor with VA in patients with RP...
April 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28403072/retinal-microvascular-alterations-related-to-diabetes-assessed-by-optical-coherence-tomography-angiography-a-cross-sectional-analysis
#11
Julien Gozlan, Pierre Ingrand, Olivier Lichtwitz, Agathe Cazet-Supervielle, Léa Benoudis, Michele Boissonnot, Samy Hadjadj, Nicolas Leveziel
Fluorescein angiography has been so far the gold-standard test to assess diabetic macular ischemia (DMI), a cause of irreversible visual impairment in diabetic patients. The aim of this study was to investigate foveal avascular zone (FAZ) and perifoveal microcirculation changes in eyes with nonproliferative diabetic retinopathy (NPDR) using optical coherence tomography angiography (OCTA), a new and noninvasive vascular imaging technique.Cross-sectional study including eyes of diabetic patients with NPDR.All patients underwent medical history, best-corrected visual acuity (BCVA) measurement, slit-lamp and fundus examination, multicolor imaging, SD-OCT, and swept-source OCT...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28400371/retinal-microvascular-network-geometry-and-cognitive-abilities-in-community-dwelling-older-people-the-lothian-birth-cohort-1936-study
#12
Sarah McGrory, Adele M Taylor, Mirna Kirin, Janie Corley, Alison Pattie, Simon R Cox, Baljean Dhillon, Joanna M Wardlaw, Fergus N Doubal, John M Starr, Emanuele Trucco, Thomas J MacGillivray, Ian J Deary
AIM: To examine the relationship between retinal vascular morphology and cognitive abilities in a narrow-age cohort of community-dwelling older people. METHODS: Digital retinal images taken at age ∼73 years from 683 participants of the Lothian Birth Cohort 1936 (LBC1936) were analysed with Singapore I Vessel Assessment (SIVA) software. Multiple regression models were applied to determine cross-sectional associations between retinal vascular parameters and general cognitive ability (g), memory, processing speed, visuospatial ability, crystallised cognitive ability and change in IQ from childhood to older age...
October 17, 2016: British Journal of Ophthalmology
https://www.readbyqxmd.com/read/28399448/apparent-diffusion-coefficient-adc-of-the-vitreous-humor-and-susceptibility-weighted-imaging-swi-of-the-retina-in-abused-children-with-retinal-hemorrhages
#13
Misun Hwang, Samuel S Shin, Matthew A Thimm, Anish Ghodadra, Christin L Sylvester, Ken Nischal, Ashok Panigrahy, Giulio Zuccoli
This study speculated that the apparent diffusion coefficient (ADC) of the vitreous humor might be altered in the setting of abusive head trauma (AHT) with retinal hemorrhages (RH). Fourty-four subjects were analyzed (n=20 AHT cases; n=24 controls). There was no statistically significant difference in normalized ADC values between the cases and controls (-0.14 and -0.08 respectively, p=0.46), but analysis of RH by susceptibility weighted imaging (SWI) compared to dilated funduscopic exam demonstrated statistically significant correlation (p=0...
April 3, 2017: Clinical Imaging
https://www.readbyqxmd.com/read/28393036/analysis-of-normal-human-retinal-vascular-network-architecture-using-multifractal-geometry
#14
Ştefan Ţălu, Sebastian Stach, Dan Mihai Călugăru, Carmen Alina Lupaşcu, Simona Delia Nicoară
AIM: To apply the multifractal analysis method as a quantitative approach to a comprehensive description of the microvascular network architecture of the normal human retina. METHODS: Fifty volunteers were enrolled in this study in the Ophthalmological Clinic of Cluj-Napoca, Romania, between January 2012 and January 2014. A set of 100 segmented and skeletonised human retinal images, corresponding to normal states of the retina were studied. An automatic unsupervised method for retinal vessel segmentation was applied before multifractal analysis...
2017: International Journal of Ophthalmology
https://www.readbyqxmd.com/read/28391812/an-enhancement-method-for-color-retinal-images-based-on-image-formation-model
#15
Li Xiong, Huiqi Li, Liang Xu
BACKGROUND AND OBJECTIVE: The good quality of color retinal image is essential for doctors to make a reliable diagnose in clinics. Due to major reasons like acquisition process and retinal diseases, most retinal images can show poor illuminance, blur and low contrast, further impeding the process of identifying the underlying retinal condition. METHODS: Image formation model of scattering is proposed to enhance color retinal images in this paper. Two parameters of this model, background illuminance and transmission map, are estimated based on extracted background and foreground...
May 2017: Computer Methods and Programs in Biomedicine
https://www.readbyqxmd.com/read/28389700/the-predictability-of-ocriplasmin-treatment-effects-is-there-consensus-among-retinal-experts-results-from-the-export-study
#16
Thomas Bertelmann, Joachim Wachtlin, Stefan Mennel, Michael J Koss, Mathias M Maier, Ricarda G Schumann, Sara Kazerounian, Hanna Daniel, Steffen Schmitz-Valckenberg
PURPOSE: To evaluate the agreement and predictability of ocriplasmin treatment effects among retinal experts (raters) by assessment of retinal imaging data of eyes treated for vitreomacular traction in nine different centers in Germany and Austria. METHODS: Retrospective cohort study. Combined confocal near-infrared scanning laser ophthalmoscopy and spectral-domain optical coherence tomography images (Spectralis® device, Heidelberg Engineering GmbH, Germany) from 136 eyes of 135 subjects were reviewed by 14 raters using an internet-based grading database and a standardized questionnaire...
April 7, 2017: Graefe's Archive for Clinical and Experimental Ophthalmology
https://www.readbyqxmd.com/read/28388705/retinal-microvasculature-and-visual-acuity-in-eyes-with-branch-retinal-vein-occlusion-imaging-analysis-by-optical-coherence-tomography-angiography
#17
Taku Wakabayashi, Tatsuhiko Sato, Chikako Hara-Ueno, Yoko Fukushima, Kaori Sayanagi, Nobuhiko Shiraki, Miki Sawa, Yasushi Ikuno, Hirokazu Sakaguchi, Kohji Nishida
Purpose: To investigate microvascular changes in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in eyes with resolved branch retinal vein occlusion (BRVO) and their association with best-corrected visual acuity (BCVA). Methods: Eighty-five eyes (82 consecutive patients) with BRVO after resolution of the macular edema were retrospectively evaluated. All patients underwent optical coherence tomography angiography (OCTA) for assessment of microvascular changes, including capillary telangiectasia, microaneurysm, and disruption of the foveal avascular zone (FAZ)...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28388703/quantitative-oct-angiography-of-the-retinal-microvasculature-and-the-choriocapillaris-in-myopic-eyes
#18
Mayss Al-Sheikh, Nopasak Phasukkijwatana, Rosa Dolz-Marco, Mansour Rahimi, Nicholas A Iafe, K Bailey Freund, SriniVas R Sadda, David Sarraf
Purpose: To study the retinal capillary microvasculature and the choriocapillaris (CC) in myopic eyes using quantitative optical coherence tomography angiography (OCTA) analysis. Methods: Macular OCTA images of 3 × 3 mm were obtained using the RTVue-XR Avanti with AngioVue. Quantitative measurements of the retinal capillary microvascular layers and the CC were analyzed using en face projection images. Vessel density and fractal dimension of the superficial and deep retinal capillary plexus, and area and density of flow reduction in the CC were analyzed, quantified, and compared with an age-matched control group...
April 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28386574/quantitative-electroencephalograms-and-neuro-optometry-a-case-study-that-explores-changes-in-electrophysiology-while-wearing-therapeutic-eyeglasses
#19
Deborah Zelinsky, Corey Feinberg
The brain is equipped with a complex system for processing sensory information, including retinal circuitry comprising part of the central nervous system. Retinal stimulation can influence brain function via customized eyeglasses at both subcortical and cortical levels. We investigated cortical effects from wearing therapeutic eyeglasses, hypothesizing that they can create measureable changes in electroencephalogram (EEG) tracings. A Z-Bell(SM) test was performed on a participant to select optimal lenses. An EEG measurement was recorded before and after the participant wore the eyeglasses...
January 2017: Neurophotonics
https://www.readbyqxmd.com/read/28386036/silent-brain-infarctions-and-leukoaraiosis-in-patients-with-retinal-ischemia-a-prospective-single-center-observational-study
#20
Amir Golsari, Diana Bittersohl, Bastian Cheng, Pia Griem, Christoph Beck, Andrea Hassenstein, Max Nedelmann, Tim Magnus, Jens Fiehler, Christian Gerloff, Götz Thomalla
BACKGROUND AND PURPOSE: We aimed to determine the incidence of co-occurring cerebral ischemia, extent of cerebral small vessel disease, and vascular risk profile of patients with acute retinal ischemia. METHODS: RETIS (Frequency of Acute Silent Brain Infarction and Systematic Evaluation of Stroke Risk in Retinal Ischemia) was a single-center, prospective, observational study comprising ophthalmologic examination, brain magnetic resonance imaging, and extensive diagnostic work-up of vascular risk factors and stroke cause...
April 6, 2017: Stroke; a Journal of Cerebral Circulation
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