Publications by authors named "Sahel J"

Background/purpose: To determine which retinal layer is primarily involved in intraretinal vascular processes associated with Toxoplasma retinochoroiditis using multimodal imaging, including optical coherence tomography angiography (OCTA).

Methods: Toxoplasma retinal lesions were analyzed through multimodal imaging, including color fundus photographs, fluorescein angiography, indocyanine green angiography, spectral-domain OCT, and OCTA.

Results: Two patients with atypical features of Toxoplasma retinochoroiditis are described in the acute phase.

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Ageing effects on spatial navigation are characterized mainly in terms of impaired allocentric strategies. However, an alternative hypothesis is that navigation difficulties in aged people are associated with deficits in processing and encoding spatial cues. We tested this hypothesis by studying how geometry and landmark cues control navigation in young and older adults in a real, ecological environment.

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Objective: To compare the impact of unilateral versus bilateral Age-related Macular Degeneration (AMD) on saccadic movements, and to show the effect of visual search training on these eye movement performances in AMD subjects. We hypothesized that unilateral and bilateral AMD subjects had abnormal saccadic performances, and that visual search training could improve their performances.

Methods: Three groups participated in visual search training: 13 elderly unilateral AMD subjects (mean age: 74.

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Purpose: To document the rod-cone dystrophy phenotype of patients with Usher syndrome type 1 (USH1) harboring MYO7A mutations.

Methods: Retrospective cohort study of 53 patients (42 families) with biallelic MYO7A mutations who underwent comprehensive examination, including functional visual tests and multimodal retinal imaging. Genetic analysis was performed either using a multiplex amplicon panel or through direct sequencing.

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Purpose: To describe outer retinal structure in patients with Best vitelliform macular dystrophy (BVMD) using spectral-domain optical coherence tomography (OCT) and correlate these results with best-corrected visual acuity (BCVA) and patient age.

Design: Retrospective cross-sectional study.

Methods: Patients with molecularly confirmed BVMD were compared with normal control subjects (NCs).

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Importance: Sensitive outcome measures for disease progression are needed for treatment trials of Stargardt disease.

Objective: To estimate the progression rate of atrophic lesions in the prospective Natural History of the Progression of Atrophy Secondary to Stargardt Disease (ProgStar) study over a 12-month period.

Design, Setting, And Participants: This multicenter prospective cohort study was conducted in an international selection of tertiary referral centers from October 21, 2013, to February 15, 2017.

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Aims: During diabetic macular oedema (DME), a spectrum of capillary abnormalities is commonly observed, ranging from microaneurysms to large microvascular abnormalities. Clinical evidence suggests that targeted photocoagulation of large microvascular abnormalities may be beneficial, but their detection is not done in a routine fashion. It was reported that they are better identified by indocyanine green angiography (ICGA) than by fluorescein angiography.

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Background: To decipher the role of monocyte-derived macrophages (Mφs) in vascular remodeling of the occluded vein following experimental branch retinal vein occlusion (BRVO).

Methods: The inflammation induced by laser-induced BRVO on mice retina was evaluated at different time points by RT-PCR looking at inflammatory markers mRNA level expression, Icam-1, Cd11b, F4/80, Ccl2, and Ccr2 and by quantification of Iba1-positive macrophage (Mφ) density on Iba1-stained retinal flatmount. Repeated intraperitoneal EdU injection combined with liposome clodronate-induced monocyte (Mo) depletion in wildtype mice was used to differentiate Mo-derived Mφs from resident Mφs.

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Introduction: The purpose of this study (Tilak Study No: TIL-001) was to evaluate the medical modules on the mobile medical application OdySight and compare them to the gold standard tests for visual acuity, contrast sensitivity, and Amsler Grid.

Methods: A total of 120 eyes were evaluated in an open-label, single-arm, prospective, single-site study during which participants performed monocular, gold standard tests for measuring visual acuity (Sloan Early Treatment Diabetic Retinopathy Study [ETDRS] letter chart at 40 cm testing distance and ETDRS letter chart at 4 m testing distance [40-cm and 4-m ETDRS, respectively), contrast sensitivity (Pelli-Robson contrast sensitivity chart [Pelli-Robson test]), and metamorphopsia/scotoma (Amsler Grid) followed by the respective modules on OdySight (also monocular). During this study, both the distance between the device and the patient's eye and room illumination were controlled by the examiner.

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Purpose: Usher syndrome (USH) is a multisensory deficiency involving vision, hearing and the vestibular system. The purpose of this study is to report on the functional data (i.e.

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Image-based angiography is a well-adapted technique to characterize vasculature, and has been used in retinal neurovascular studies. Because the microvasculature is of particular interest, being the site of exchange between blood and tissue, a high spatio-temporal resolution is required, implying the use of adaptive optics ophthalmoscopes with a high frame rate. Creating the opportunity for decoupled stimulation and imaging of the retina makes the use of near infrared (NIR) imaging light desirable, while the need for a large field of view and a lack of distortion implies the use of a flood illumination-based setup.

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Carotenoid-containing oil droplets in the avian retina act as cut-off filters to enhance colour discrimination. We report a confocal resonance Raman investigation of the oil droplets of the domestic chicken, Gallus gallus domesticus. We show that all carotenoids present are in a constrained conformation, implying a locus in specific lipid binding sites.

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Advances in preclinical research are now being translated into innovative clinical solutions for blindness.

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We demonstrate near-infrared autofluorescence (NIRAF) imaging of retinal pigment epithelial (RPE) cells in healthy volunteers and patients using a 757 nm excitation source in adaptive optics scanning laser ophthalmoscopy (AOSLO). NIRAF excited at 757 nm and collected in an emission band from 778 to 810 nm produced a robust NIRAF signal, presumably arising from melanin, and revealed the typical hexagonal mosaic of RPE cells at most eccentricities imaged within the macula of normal eyes. Several patterns of altered NIRAF structure were seen in patients, including disruption of the NIRAF over a drusen, diffuse hyper NIRAF signal with loss of individual cell delineation in a case of non-neovascular age-related macular degeneration (AMD), and increased visibility of the RPE mosaic under an area showing loss of photoreceptors.

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Purpose: To evaluate the feasibility, safety, and efficiency of an adapted surgical procedure used for postmarket Argus II implantations, so as to lower risks of postoperative hypotony or conjunctivoscleral erosion, and to describe the observed anatomic characteristics of the positioning of the implanted array.

Design: Single-arm prospective multicenter clinical trial.

Participants: Eighteen consecutive patients with end-stage retinitis pigmentosa.

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In this Letter, we propose a way to better understand the impact of dynamic ocular aberrations in the axial resolution of nonconfocal adaptive optics (AO) ophthalmoscopes via a simulation of the 3D PSF in the retina for various AO-loop rates. We then use optical incoherence tomography, a method enabling the generation of tomographic retinal cross sections in incoherent imaging systems, to evaluate the benefits of a fast AO-loop rate on axial resolution and, consequently, on AO-corrected retinal image quality. We used the PARIS AO flood-illumination ophthalmoscope for this study, where retinal images from different focal planes at an AO-loop rate of 10 and 50 Hz were acquired.

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Importance: A precise phenotypic characterization of retinal dystrophies is needed for disease modeling as a basis for future therapeutic interventions.

Objective: To compare genotype, phenotype, and structural changes in patients with rod-cone dystrophy (RCD) associated with mutations in PDE6A or PDE6B.

Design, Setting, And Participants: In a retrospective cohort study conducted in Paris, France, from January 2007 to September 2017, 54 patients from a cohort of 1095 index patients with RCD underwent clinical examination, including personal and familial history, best-corrected visual acuity (BCVA), color vision, slitlamp examination, full-field electroretinography, kinetic visual fields (VFs), retinophotography, optical coherence tomography, near-infrared fundus autofluorescence, and short-wavelength fundus autofluorescence imaging.

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Neuroimaging modalities such as MRI and EEG are able to record from the whole brain, but this comes at the price of either limited spatiotemporal resolution or limited sensitivity. Here, we show that functional ultrasound imaging (fUS) of the brain is able to assess local changes in cerebral blood volume during cognitive tasks, with sufficient temporal resolution to measure the directional propagation of signals. In two macaques, we observed an abrupt transient change in supplementary eye field (SEF) activity when animals were required to modify their behaviour associated with a change of saccade tasks.

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Patients affected by retinitis pigmentosa, an inherited retinal disease, experience a decline in vision due to photoreceptor degeneration leading to irreversible blindness. Rod-derived cone viability factor (RdCVF) is the most promising mutation-independent treatment today. To identify pathologic processes leading to secondary cone photoreceptor dysfunction triggering central vision loss of these patients, we model the stimulation by RdCVF of glucose uptake in cones and glucose metabolism by aerobic glycolysis.

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Inherited retinal disorders (IRD) represent clinically and genetically heterogeneous diseases. To date, pathogenic variants have been identified in ~260 genes. Albeit that many genes are implicated in IRD, for 30-50% of the cases, the gene defect is unknown.

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The choroid is a highly vascularized tissue supplying the retinal pigment epithelium and photoreceptors. Its implication in retinal diseases is gaining increasing interest. However, investigating the anatomy and flow of the choroid remains challenging.

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We describe recent technological progress in multimodal en face full-field optical coherence tomography that has allowed detection of slow and fast dynamic processes in the eye. We show that by combining static, dynamic and fluorescence contrasts we can achieve label-free high-resolution imaging of the retina and anterior eye with temporal resolution from milliseconds to several hours, allowing us to probe biological activity at subcellular scales inside 3D bulk tissue. Our setups combine high lateral resolution over a large field of view with acquisition at several hundreds of frames per second which make it a promising tool for clinical applications and biomedical studies.

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Purpose: To compare the effectiveness and the safety of three eye reconstruction techniques with porous bioceramic implantation in facial surgery: the "four petals" eye evisceration (EE) technique, the "russian doll" EE technique and the enucleation with "on-the-table" evisceration technique.

Methods: Retrospective review of patients who underwent surgical orbit reconstruction with primary placement of a porous bioceramic orbital implant using three techniques at Quinze-Vingts National Center (Paris, France). We compared outcomes of three surgical orbit reconstruction techniques: the "four petal" EE technique, the "russian doll" EE technique and the enucleation with "on-the-table" evisceration technique.

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Article Synopsis
  • Scientists are studying how the brain changes when people lose their vision, particularly in patients with a condition called retinitis pigmentosa.
  • They looked at two groups: one with some central vision left and another that was completely blind, to see how losing different parts of vision affects the brain's white matter.
  • The results showed that as people lose their vision, the brain reorganizes itself, which might help them adapt to their new way of seeing and improve other senses.
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