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*** learning applied to the oxygen induced retinopathy model

Annals of Eye Science 2018年第1期 431-431页

作者： Javier Mazzaferri Bruno Larrivée Przemyslaw Sapieha santiago costantino Department of Biochemistry Maisonneuve-Rosemont Hospital Research CentreUniversity of MontrealMontrealQuebecCanada Department of Ophthalmology Maisonneuve-Rosemont Hospital Research CentreUniversity of MontrealMontrealQuebecCanada Departement of Neuroscience McGill UniversityMontrealQuebecCanada

Background:The oxygen induced retinopathy rodent model is widely used,notably for the assessment of developmental dystrophies in preclinical studies of vascular retinal ***,the quantification of vessel tufts and avascular regions is computed manually from flat mounted retinas imaged using fluorescent probes that highlight the vascular ***,such manual measurements are time-consuming and hampered by user variability and bias,thus a rapid and objective alternative is ***:We employ a machine learning approach to segment and characterize vascular *** proposed quantitative retinal vascular assessment(QuRVA)technique uses quadratic discrimination analysis and morphological techniques to provide reliable measurements of vascular density and pathological vascular tuft regions,devoid of user intervention within *** algorithms allow also delineating the whole vasculature network,and identifying and analyzing avascular ***:Our first experiment shows the high degree of error and variability of manual *** consequence,we developed a set of algorithms to perform this task *** benchmark and validate the results of our analysis pipeline using the consensus of several manually curated segmentations using commonly used computer *** describe the method,provide details for reproducing the algorithm,and validate all aspects of the ***:Manual and semi-automated procedures for tuft detection present strong fluctuations among users,demonstrating the need for fast and unbiased tools in this highly active research field with tremendous implications for basic research and industry.

关键词： Oxygen induced retinopathy(OIR) machine learning image segmentation

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*** rigidity is correlated with glaucomatous structural damage

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Annals of Eye Science 2019年第1期 201-201页

作者： Diane N.Sayah Javier Mazzaferri Denise Descovich santiago costantino Mark R.Lesk Maisonneuve-Rosemont Hospital Research Center MontrealQCCanada Department of Ophthalmology Faculty of MedicineUniversitéde MontréalMontrealQCCanada Centre Universitaire d'ophtalmologie de l'Universitéde Montréal de l'Hôpital Maisonneuve-Rosemont CIUSSS-EMontrealQCCanada

Background:The rigidity of the corneoscleral shell is an important biomechanical property which could be relevant in the pathophysiology of open-angle glaucoma(OAG).This study aims to evaluate the relationship between ocular rigidity(OR)and glaucomatous damage as represented by structural optical coherence tomography(OCT)-based parameters such as retinal nerve fiber layer(RNFL)and ganglion cell layer+inner plexiform layer(GCL+IPL)*** parameters characterize the retinal layers that contain neuronal structures that form the optic ***:Sixty-six subjects(37 with early OAG,11 with moderate to advanced OAG,16 healthy)were recruited in this *** measurements were carried out using a non-invasive clinical method developed by our *** described in Beaton et al.(2015),this method,which is based on Friedenwald’s equation,involves video-rate OCT imaging and automated choroidal segmentation,as well as dynamic contour tonometry to calculate the OR *** and macular GCL thicknesses were acquired using the Cirrus SD-OCT(Carl-Zeiss Meditec,Dublin,CA,USA).Correlations between OR and structural parameters in all 66 eyes were assessed using ***:Significant correlations were found between OR and the average GCL+IPL thickness(r=0.355,P=0.004)as well as the minimum GCL+IPL thickness(r=0.340,P=0.006).Direct correlations were also found between OR and RNFL thickness in the inferior quadrant(r=0.258,P=0.036)and inferior clock hour(r=0.313,P=0.011).Conclusions:In this study,we found a positive correlation between structural OCT-based parameters and OR,perhaps indicating more structural damage in less rigid *** findings could provide insight unto the pathophysiology of *** investigation is warranted to confirm the role of OR in glaucoma and elucidate whether there is a subgroup of patients for which OR plays a greater role.

关键词： Ocular rigidity(OR) retinal nerve fiber layer(RNFL) ganglion cell complex open-angle glaucoma(OAG)

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AB036. Pulsatile choroidal blood flow (PCBF) in the glaucoma spectrum-preliminary results obtained with a novel optical method

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Annals of Eye Science 2018年第1期 442-442页

作者： Wenzhen Zuo Diane N.Sayah Javier Mazzaferri santiago costantino Mark R.Lesk Centre de recherche de l'hôpital Maisonneuve-Rosemont MontréalQCCanada Facultéde Médecine Universitéde MontréalMontrealQCCanada Department of Ophthalmology Universitéde MontréalMontrealQCCanada

Background:Decrease of ocular blood flow has been linked to the pathogenesis of ocular diseases such as glaucoma and age-related macular *** methods that measure the pulsatile blood flow have major limitations,including the assumption that ocular rigidity is the same in all *** group has recently developed a new method to measure the pulsatile choroidal volume change by direct visualization of the choroid with OCT imaging and automated *** goal in this study is to describe the distribution of PCBF in a healthy Caucasian ***:Fifty-one subjects were recruited from the Maisonneuve-Rosemont Hospital Ophthalmology Clinic and underwent PCBF measurement in one *** distribution of PCBF in healthy eyes was ***:The distribution of PCBF among the healthy eyes was found to be 3.94±1.70µL with this ***:This study demonstrates the normal range of PCBF values obtained in a healthy Caucasian *** technique could be used for further investigation of choroid pulsatility and to study glaucoma pathophysiology.

关键词： Pulsatile choroid blood flow(PCBF) glaucoma pathophysiology novel method

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AB091.A novel method for the measurement of pulsatile choroidal blood flow based on video-rate OCT imaging and automated segmentation of the choroid:description and reproducibility

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Annals of Eye Science 2018年第1期 497-497页

作者： Diane N.Sayah Wenzhen Zuo Javier Mazzaferri Luke Beaton santiago costantino Mark R.Lesk Centre de recherche de l'Hôpital Maisonneuve-Rosemont MontrealQCCanada Département d'Ophtalmologie Universitéde MontréalMontrealQCCanada Facultéde Médecine Universitéde MontréalMontrealQCCanada

Background:Over the years,a variety of non-invasive techniques have been developed to allow the measurement of blood flow in living human ***,none of the existing techniques has yet been adopted in clinical practice due to their limitations and lack of ***,no reliable technique is currently available to measure the pulsatile choroidal blood flow(PCBF).We propose a novel method based on video-rate optical coherence tomography(OCT)imaging and automated segmentation to measure the pulsatile component of choroidal blood flow in vivo,and demonstrate its ***:Adapted from our earlier work(Beaton et al.),this method uses video-rate OCT with enhanced depth imaging and automated segmentation of the choroid to measure the pulsatile choroidal volume *** is carried out at the fundus for less than a minute at 7 *** each frame,choroidal thickness(CT)is measured by a segmentation algorithm based on graph cuts using an edge-probability weighting *** algorithm computes the CT change corresponding to choroidal filling over the time-series and subsequently derives the pulsatile choroidal volume change through an approximate model of the ***-eight subjects were recruited from the Maisonneuve-Rosemont Hospital and PCBF was measured twice in one eye within the same session and by a single *** was assessed using the Bland-Altman plot and Intraclass correlation coefficient as calculated with ***:Two measurements of PCBF were successfully obtained for each eye using our *** average measures ICC for choroidal volume change was 0.929(95%CI,0.881,0.958),showing good to excellent *** Bland-Altman plot and Pearson coefficient(r=0.840,P<0.001)showed agreement and a strong correlation respectively between intra-session measurement of OR in all examined ***:This study confirms the high repeatability of pulsatile choroidal blood flow measurements obtained with our

关键词： Pulsatile choroidal blood flow(PCBF) optical coherence tomography(OCT) novel technique repeatability

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AB034. In vivo laser-mediated retinal ganglion cell optoporation using Kv1.1 conjugated gold nanoparticles

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Annals of Eye Science 2018年第1期 440-440页

作者： Ariel M.Wilson Javier Mazzaferri Éric Bergeron Sergiy Patskovsky santiago costantino Michel Meunier Przemyslaw Sapieha Department of Engineering Physics École PolytechniqueMontrealQCCanada Department of Biochemistry Hôpital Maisonneuve-RosemontMontrealQCCanada

Background:There is a current void in efficient,cell-specific,retinal drug delivery systems,thus developing a safe,effective,selective drug delivery system would open novel therapeutic *** previously demonstrated that femtosecond(fs)laser irradiation can transfect DNA plasmids into cultured cells in the presence of gold nanoparticles(AuNPs).These AuNPs locally amplify laser energy at a submicron range creating transient pores allowing exogenous genetic material or cell impermeable dyes to enter the ***,we sought out to selectively optoporate retinal cells in vivo with functionalized AuNPs and a 800 nm femtosecond(fs)***:The cell-surface Kv1.1 voltage-gated channel was chosen to selectively target retinal ganglion cells(RGC)in the rat ***-capped spherical 100 nm AuNPs functionalized with orthopyridyl-disulfide-poly(ethylene glycol)(5 kDa)-N-hydroxysuccinimide(OPSS-PEG-NHS)conjugated to a Kv1.1 monoclonal antibody were injected intravitreally in Sprague Dawley rats 3 hours prior to irradiation,concomitantly to a FITC-dextran dye to detect *** eyes of anesthetized rats were placed in the beam path of a laser system consisting of an 800 nm,100 fs laser and a Heidelberg Spectralis HRA ophthalmoscope for fundus *** rat retina was irradiated at powers ranging from 20-750 mW,the eyes fixed in 4%paraformaldehyde,dissected,rinsed,mounted and imaged by confocal ***:Our novel laser system coupled to a Heidelberg ophthalmoscope allowed for a clear visualisation of the rat ocular fundus.A timecourse of AuNP intravitreal injections revealed that optimal nanoparticle dispersion on the retinal surface occurred at 3 hours post *** Kv1.1-AuNP and FITC-dextran intravitreal injection and incubation,irradiation at 120-750 mW resulted in FITC uptake by retinal ***:Since living biological tissues absorb energy very weakly at 800 nm,this non-invasive tool may provide a safe,cost effecti

关键词： Nanoparticle laser optoporation

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