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Hofstetter S, Sabbah N, Mohand-Saïd S, Sahel JA, Habas C, Safran AB, Amedi A. The development of white matter structural changes during the process of deterioration of the visual field. Sci Rep 2019; 9:2085. [PMID: 30765782 PMCID: PMC6375971 DOI: 10.1038/s41598-018-38430-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 12/27/2018] [Indexed: 12/02/2022] Open
Abstract
Emerging evidence suggests that white matter plasticity in the adult brain is preserved after sensory and behavioral modifications. However, little is known about the progression of structural changes during the process of decline in visual input. Here we studied two groups of patients suffering from advanced retinitis pigmentosa with specific deterioration of the visual field: patients who had lost their peripheral visual field, retaining only central (“tunnel”) vision, and blind patients with complete visual field loss. Testing of these homogeneous groups made it possible to assess the extent to which the white matter is affected by loss of partial visual input and whether partially preserved visual input suffices to sustain stability in tracts beyond the primary visual system. Our results showed gradual changes in diffusivity that are indicative of degenerative processes in the primary visual pathway comprising the optic tract and the optic radiation. Interestingly, changes were also found in tracts of the ventral stream and the corticospinal fasciculus, depicting a gradual reorganisation of these tracts consequentially to the gradual loss of visual field coverage (from intact perception to partial vision to complete blindness). This reorganisation may point to microstructural plasticity underlying adaptive behavior and cross-modal integration after partial visual deprivation.
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Affiliation(s)
- Shir Hofstetter
- Department of Medical Neurobiology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, 91220, Jerusalem, Israel. .,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, 91220, Jerusalem, Israel.
| | - Norman Sabbah
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, F-75012, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, F-75012, Paris, France.,Fondation Ophtalmologique A. de Rothschild, F-75019, Paris, France.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA
| | - Christophe Habas
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, F-75012, Paris, France.,Centre de Neuro-Imagerie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, F-75012, France
| | - Avinoam B Safran
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC 1423, F-75012, Paris, France.,Department of Clinical Neurosciences, Geneva University School of Medicine, Geneva, Switzerland
| | - Amir Amedi
- Department of Medical Neurobiology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, 91220, Jerusalem, Israel. .,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, 91220, Jerusalem, Israel. .,Sorbonne Université, INSERM, CNRS, Institut de la Vision, F-75012, Paris, France. .,The Cognitive Science Program, The Hebrew University of Jerusalem, 91220, Jerusalem, Israel.
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Sanda N, Cerliani L, Authié CN, Sabbah N, Sahel JA, Habas C, Safran AB, Thiebaut de Schotten M. Visual brain plasticity induced by central and peripheral visual field loss. Brain Struct Funct 2018; 223:3473-3485. [PMID: 29936553 PMCID: PMC6132657 DOI: 10.1007/s00429-018-1700-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 06/15/2018] [Indexed: 01/22/2023]
Abstract
Disorders that specifically affect central and peripheral vision constitute invaluable models to study how the human brain adapts to visual deafferentation. We explored cortical changes after the loss of central or peripheral vision. Cortical thickness (CoTks) and resting-state cortical entropy (rs-CoEn), as a surrogate for neural and synaptic complexity, were extracted in 12 Stargardt macular dystrophy, 12 retinitis pigmentosa (tunnel vision stage), and 14 normally sighted subjects. When compared to controls, both groups with visual loss exhibited decreased CoTks in dorsal area V3d. Peripheral visual field loss also showed a specific CoTks decrease in early visual cortex and ventral area V4, while central visual field loss in dorsal area V3A. Only central visual field loss exhibited increased CoEn in LO-2 area and FG1. Current results revealed biomarkers of brain plasticity within the dorsal and the ventral visual streams following central and peripheral visual field defects.
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Affiliation(s)
- Nicolae Sanda
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France.
- INSERM, U968, Institut de la Vision, 75012, Paris, France.
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France.
- Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012, Paris, France.
- Department of Clinical Neurosciences, Geneva University Hospital and Geneva University School of Medicine, Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland.
| | - Leonardo Cerliani
- Frontlab, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et la moelle (ICM), Hôpital Pitié-Salpêtrière, Boulevard de l'hôpital, 75013, Paris, France
- Brain Connectivity and Behaviour Group, Sorbonne University, Paris, France
- Department of Psychiatry, Academic Medical Centre, Amsterdam, The Netherlands
- Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, The Netherlands
| | - Colas N Authié
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France
- INSERM, U968, Institut de la Vision, 75012, Paris, France
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France
- Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012, Paris, France
| | - Norman Sabbah
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France
- INSERM, U968, Institut de la Vision, 75012, Paris, France
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France
- Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012, Paris, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France
- INSERM, U968, Institut de la Vision, 75012, Paris, France
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France
- Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012, Paris, France
- Institute of Ophthalmology, University College of London, London, UK
- Fondation Ophtalmologique Adolphe de Rothschild, Paris, France
- Department of Ophthalmology, School of Medicine, University of Pittsburg, Pittsburg, USA
| | - Christophe Habas
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France
- INSERM, U968, Institut de la Vision, 75012, Paris, France
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France
- Centre de Neuroimagerie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, 75012, Paris, France
| | - Avinoam B Safran
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, 75012, Paris, France
- INSERM, U968, Institut de la Vision, 75012, Paris, France
- CNRS, UMR 7210, Institut de la Vision, 75012, Paris, France
- Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012, Paris, France
- Department of Clinical Neurosciences, Geneva University Hospital and Geneva University School of Medicine, Gabrielle-Perret-Gentil 4, 1205, Geneva, Switzerland
| | - Michel Thiebaut de Schotten
- Frontlab, UPMC Univ Paris 06, Inserm, CNRS, Institut du cerveau et la moelle (ICM), Hôpital Pitié-Salpêtrière, Boulevard de l'hôpital, 75013, Paris, France
- Brain Connectivity and Behaviour Group, Sorbonne University, Paris, France
- Groupe d'Imagerie Neurofonctionnelle, Institut des Maladies Neurodégénératives, UMR 5293, CNRS, CEA University of Bordeaux, Bordeaux, France
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Authié CN, Berthoz A, Sahel JA, Safran AB. Adaptive Gaze Strategies for Locomotion with Constricted Visual Field. Front Hum Neurosci 2017; 11:387. [PMID: 28798674 PMCID: PMC5529417 DOI: 10.3389/fnhum.2017.00387] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 07/12/2017] [Indexed: 11/13/2022] Open
Abstract
In retinitis pigmentosa (RP), loss of peripheral visual field accounts for most difficulties encountered in visuo-motor coordination during locomotion. The purpose of this study was to accurately assess the impact of peripheral visual field loss on gaze strategies during locomotion, and identify compensatory mechanisms. Nine RP subjects presenting a central visual field limited to 10-25° in diameter, and nine healthy subjects were asked to walk in one of three directions-straight ahead to a visual target, leftward and rightward through a door frame, with or without obstacle on the way. Whole body kinematics were recorded by motion capture, and gaze direction in space was reconstructed using an eye-tracker. Changes in gaze strategies were identified in RP subjects, including extensive exploration prior to walking, frequent fixations of the ground (even knowing no obstacle was present), of door edges, essentially of the proximal one, of obstacle edge/corner, and alternating door edges fixations when approaching the door. This was associated with more frequent, sometimes larger rapid-eye-movements, larger movements, and forward tilting of the head. Despite the visual handicap, the trajectory geometry was identical between groups, with a small decrease in walking speed in RPs. These findings identify the adaptive changes in sensory-motor coordination, in order to ensure visual awareness of the surrounding, detect changes in spatial configuration, collect information for self-motion, update the postural reference frame, and update egocentric distances to environmental objects. They are of crucial importance for the design of optimized rehabilitation procedures.
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Affiliation(s)
- Colas N Authié
- UPMC Université Paris 06, UMR S968, Institut de la Vision, Sorbonne UniversitésParis, France.,Institut National de la Santé et de la Recherche Médicale, U968, Institut de la VisionParis, France.,Centre National de la Recherche Scientifique, UMR 7210, Institut de la VisionParis, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Institut National de la Santé et de la Recherche Médicale-DHOS CIC 1423Paris, France
| | - Alain Berthoz
- Equipe Pr Alain Berthoz Professeur Emérite au Collège de FranceParis, France
| | - José-Alain Sahel
- UPMC Université Paris 06, UMR S968, Institut de la Vision, Sorbonne UniversitésParis, France.,Institut National de la Santé et de la Recherche Médicale, U968, Institut de la VisionParis, France.,Centre National de la Recherche Scientifique, UMR 7210, Institut de la VisionParis, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Institut National de la Santé et de la Recherche Médicale-DHOS CIC 1423Paris, France.,Institute of Ophthalmology, University College LondonLondon, United Kingdom.,Fondation Ophtalmologique Adolphe de RothschildParis, France.,Department of Ophthalmology, School of Medicine, University of PittsburghPittsburgh, PA, United States
| | - Avinoam B Safran
- UPMC Université Paris 06, UMR S968, Institut de la Vision, Sorbonne UniversitésParis, France.,Institut National de la Santé et de la Recherche Médicale, U968, Institut de la VisionParis, France.,Centre National de la Recherche Scientifique, UMR 7210, Institut de la VisionParis, France.,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Institut National de la Santé et de la Recherche Médicale-DHOS CIC 1423Paris, France.,Département des Neurosciences, Université de GenèveGeneva, Switzerland
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Sabbah N, Sanda N, Authié CN, Mohand-Saïd S, Sahel JA, Habas C, Amedi A, Safran AB. Reorganization of early visual cortex functional connectivity following selective peripheral and central visual loss. Sci Rep 2017; 7:43223. [PMID: 28233790 PMCID: PMC5324137 DOI: 10.1038/srep43223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/20/2017] [Indexed: 12/27/2022] Open
Abstract
Behavioral alterations emerging after central or peripheral vision loss suggest that cerebral reorganization occurs for both the afferented and deafferented early visual cortex (EVC). We explored the functional reorganization of the central and peripheral EVC following visual field defects specifically affecting central or peripheral vision. Compared to normally sighted, afferented central and peripheral EVC enhance their functional connectivity with areas involved in visual processing, whereas deafferented central and peripheral EVC increase their functional connectivity with more remote regions. The connectivity pattern of afferented EVC suggests adaptive changes that might enhance the visual processing capacity whereas the connectivity pattern of deafferented EVC may reflect the involvement of these regions in high-order mechanisms. Characterizing and understanding the plastic changes induced by these visual defects is essential for any attempt to develop efficient rehabilitation strategies.
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Affiliation(s)
- Norman Sabbah
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - Nicolae Sanda
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Service de neurologie, Hôpital Foch, Suresnes, France
| | - Colas N Authié
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - Saddek Mohand-Saïd
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Institute of Ophthalmology, University College of London, United Kingdom.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, US
| | - Christophe Habas
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre de neuroimagerie, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, F-75012, France
| | - Amir Amedi
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Department of Medical Neurobiology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91220, Israel.,The Edmond and Lily Safra Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem 91220, Israel.,The Cognitive Science Program, The Hebrew University of Jerusalem, Jerusalem 91220, Israel
| | - Avinoam B Safran
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, F-75012, France.,INSERM, U968, Institut de la Vision, Paris, F-75012, France.,CNRS, UMR 7210, Institut de la Vision, Paris, F-75012, France.,Centre d'investigation clinique, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, F-75012, France.,Department of Clinical Neurosciences, Geneva University School of Medicine, Geneva, Switzerland
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Sabbah N, Authié CN, Sanda N, Mohand-Saïd S, Sahel JA, Safran AB, Habas C, Amedi A. Increased functional connectivity between language and visually deprived areas in late and partial blindness. Neuroimage 2016; 136:162-73. [DOI: 10.1016/j.neuroimage.2016.04.056] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/12/2016] [Accepted: 04/22/2016] [Indexed: 01/09/2023] Open
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da Cruz L, Dorn JD, Humayun MS, Dagnelie G, Handa J, Barale PO, Sahel JA, Stanga PE, Hafezi F, Safran AB, Salzmann J, Santos A, Birch D, Spencer R, Cideciyan AV, de Juan E, Duncan JL, Eliott D, Fawzi A, Olmos de Koo LC, Ho AC, Brown G, Haller J, Regillo C, Del Priore LV, Arditi A, Greenberg RJ. Five-Year Safety and Performance Results from the Argus II Retinal Prosthesis System Clinical Trial. Ophthalmology 2016; 123:2248-54. [PMID: 27453256 DOI: 10.1016/j.ophtha.2016.06.049] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/04/2016] [Accepted: 06/17/2016] [Indexed: 12/16/2022] Open
Abstract
PURPOSE The Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc, Sylmar, CA) was developed to restore some vision to patients blind as a result of retinitis pigmentosa (RP) or outer retinal degeneration. A clinical trial was initiated in 2006 to study the long-term safety and efficacy of the Argus II System in patients with bare or no light perception resulting from end-stage RP. DESIGN Prospective, multicenter, single-arm clinical trial. Within-patient controls included the nonimplanted fellow eye and patients' native residual vision compared with their vision with the Argus II. PARTICIPANTS Thirty participants in 10 centers in the United States and Europe. METHODS The worse-seeing eye of blind patients was implanted with the Argus II. Patients wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. MAIN OUTCOME MEASURES The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by 3 computer-based, objective tests. Secondary measures included functional vision performance on objectively scored real-world tasks. RESULTS Twenty-four of 30 patients remained implanted with functioning Argus II Systems at 5 years after implantation. Only 1 additional serious adverse event was experienced after the 3-year time point. Patients performed significantly better with the Argus II on than off on all visual function tests and functional vision tasks. CONCLUSIONS The 5-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind as a result of RP. The Argus II is the first and only retinal implant to have market approval in the European Economic Area, the United States, and Canada.
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Affiliation(s)
- Lyndon da Cruz
- Department of Vitreoretinal Surgery, Moorfields Eye Hospital, NHS Foundation Trust, NIHR Moorfields Biomedical Research Centre, London, United Kingdom and Department of Brain Science, University College London (UCL)
| | - Jessy D Dorn
- Second Sight Medical Products, Inc, Sylmar, California.
| | - Mark S Humayun
- University of Southern California, Los Angeles, California
| | - Gislin Dagnelie
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | - James Handa
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | | | - José-Alain Sahel
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; Sorbonne Universities-UPMC Paris-6, and Institut de la Vision, Paris, France; Rothschild Ophthalmology Foundation, Paris, France
| | - Paulo E Stanga
- Manchester Royal Eye Hospital, Manchester Vision Regeneration (MVR) Laboratory at NIHR/Wellcome Trust Manchester CRF, and Manchester Academic Health Science Centre and Centre for Ophthalmology and Vision Research, Institute of Human Development, University of Manchester, Manchester, United Kingdom
| | - Farhad Hafezi
- University of Southern California, Los Angeles, California; ELZA Institute, Zurich, Switzerland; Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | - Avinoam B Safran
- Sorbonne Universities-UPMC Paris-6, and Institut de la Vision, Paris, France; Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | - Joel Salzmann
- Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | - Arturo Santos
- Centro de Retina Medica y Quirúrgica, SC, and Tecnologico de Monterrey, Guadalajara, Mexico
| | - David Birch
- Retina Foundation of the Southwest, Dallas, Texas
| | | | - Artur V Cideciyan
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eugene de Juan
- University of California, San Francisco, San Francisco, California
| | - Jacque L Duncan
- University of California, San Francisco, San Francisco, California
| | - Dean Eliott
- University of Southern California, Los Angeles, California; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Amani Fawzi
- University of Southern California, Los Angeles, California; Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | | | - Allen C Ho
- Wills Eye Hospital, Philadelphia, Pennsylvania
| | - Gary Brown
- Wills Eye Hospital, Philadelphia, Pennsylvania
| | - Julia Haller
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland; Wills Eye Hospital, Philadelphia, Pennsylvania
| | | | - Lucian V Del Priore
- Columbia University, New York, and Storm Eye Institute, Charleston, South Carolina
| | - Aries Arditi
- Lighthouse Guild, New York, and Visibility Metrics, LLC, Chappaqua, New York
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7
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Ho AC, Humayun MS, Dorn JD, da Cruz L, Dagnelie G, Handa J, Barale PO, Sahel JA, Stanga PE, Hafezi F, Safran AB, Salzmann J, Santos A, Birch D, Spencer R, Cideciyan AV, de Juan E, Duncan JL, Eliott D, Fawzi A, Olmos de Koo LC, Brown GC, Haller JA, Regillo CD, Del Priore LV, Arditi A, Geruschat DR, Greenberg RJ. Long-Term Results from an Epiretinal Prosthesis to Restore Sight to the Blind. Ophthalmology 2015; 122:1547-54. [PMID: 26162233 DOI: 10.1016/j.ophtha.2015.04.032] [Citation(s) in RCA: 192] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Retinitis pigmentosa (RP) is a group of inherited retinal degenerations leading to blindness due to photoreceptor loss. Retinitis pigmentosa is a rare disease, affecting only approximately 100 000 people in the United States. There is no cure and no approved medical therapy to slow or reverse RP. The purpose of this clinical trial was to evaluate the safety, reliability, and benefit of the Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc, Sylmar, CA) in restoring some visual function to subjects completely blind from RP. We report clinical trial results at 1 and 3 years after implantation. DESIGN The study is a multicenter, single-arm, prospective clinical trial. PARTICIPANTS There were 30 subjects in 10 centers in the United States and Europe. Subjects served as their own controls, that is, implanted eye versus fellow eye, and system on versus system off (native residual vision). METHODS The Argus II System was implanted on and in a single eye (typically the worse-seeing eye) of blind subjects. Subjects wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina. MAIN OUTCOME MEASURES The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by 3 computer-based, objective tests. RESULTS A total of 29 of 30 subjects had functioning Argus II Systems implants 3 years after implantation. Eleven subjects experienced a total of 23 serious device- or surgery-related adverse events. All were treated with standard ophthalmic care. As a group, subjects performed significantly better with the system on than off on all visual function tests and functional vision assessments. CONCLUSIONS The 3-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind from RP. Earlier results from this trial were used to gain approval of the Argus II by the Food and Drug Administration and a CE mark in Europe. The Argus II System is the first and only retinal implant to have both approvals.
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Affiliation(s)
- Allen C Ho
- Wills Eye Hospital, Philadelphia, Pennsylvania.
| | - Mark S Humayun
- University of Southern California, Los Angeles, California
| | - Jessy D Dorn
- Second Sight Medical Products, Sylmar, California
| | - Lyndon da Cruz
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom; NHIR Moorfields Biomedical Research Centre, London, United Kingdom
| | - Gislin Dagnelie
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | - James Handa
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | | | - José-Alain Sahel
- Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; ELZA Institute, Zurich, Switzerland
| | - Paulo E Stanga
- Manchester Royal Eye Hospital, Manchester, United Kingdom; Manchester Vision Regeneration Lab at National Institute for Health Research/Wellcome Trust Manchester CRF, Manchester, United Kingdom; Manchester Academic Health Science Centre and Centre for Ophthalmology and Vision Research, Institute of Human Development, University of Manchester, Manchester, United Kingdom
| | - Farhad Hafezi
- University of Southern California, Los Angeles, California; Hôpitaux Universitaires de Genève, Geneva, Switzerland; ELZA Institute, Zurich, Switzerland
| | - Avinoam B Safran
- Hôpitaux Universitaires de Genève, Geneva, Switzerland; Sorbonne Universities - UPMC Paris-6, and Institut de la Vision, Paris, France
| | - Joel Salzmann
- Hôpitaux Universitaires de Genève, Geneva, Switzerland
| | - Arturo Santos
- Centro de Retina Medica y Quirúrgica, SC, Guadalajara, Mexico; Tecnologico de Monterrey, Guadalajara, Mexico
| | - David Birch
- Retina Foundation of the Southwest, Dallas, Texas
| | | | - Artur V Cideciyan
- Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eugene de Juan
- University of California, San Francisco, San Francisco, California
| | - Jacque L Duncan
- University of California, San Francisco, San Francisco, California
| | - Dean Eliott
- University of Southern California, Los Angeles, California; Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Amani Fawzi
- University of Southern California, Los Angeles, California; Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | | | | | - Julia A Haller
- Wills Eye Hospital, Philadelphia, Pennsylvania; Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | | | - Lucian V Del Priore
- Columbia University, New York, New York; Storm Eye Institute, Charleston, South Carolina
| | - Aries Arditi
- Lighthouse Guild, New York, New York; Visibility Metrics, LLC, Chappaqua, New York
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Sabbah N, Authié CN, Sanda N, Mohand-Said S, Sahel JA, Safran AB. Importance of eye position on spatial localization in blind subjects wearing an Argus II retinal prosthesis. Invest Ophthalmol Vis Sci 2014; 55:8259-66. [PMID: 25414187 DOI: 10.1167/iovs.14-15392] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE With a retinal prosthesis connected to a head-mounted camera (camera-connected prosthesis [CC-P]), subjects explore the visual environment through head-scanning movements. As eye and camera misalignment might alter the spatial localization of images generated by the device, we investigated if such misalignment occurs in blind subjects wearing a CC-P and whether it impacts spatial localization, even years after the implantation. METHODS We studied three subjects blinded by retinitis pigmentosa, fitted with a CC-P (Argus II) 4 years earlier. Eye/head movements were video recorded as subjects tried to localize a visual target. Pointing coordinates were collected as subjects were requested to orient their gaze toward predetermined directions, and to point their finger to the corresponding perceived spot locations on a touch screen. Finally, subjects were asked to give a history of their everyday behavior while performing visually controlled grasping tasks. RESULTS Misaligned head and gaze directions occurred in all subjects during free visual search. Pointing coordinates were collected in two subjects and showed that median pointing directions shifted toward gaze direction. Reportedly all subjects were unable to accurately determine their eye position, and they developed adapted strategies to perform visually directed movements. CONCLUSIONS Eye position affected perceptual localization of images generated by the Argus II prosthesis, and consequently visuomotor coordination, even 4 years following implantation. Affected individuals developed strategies for visually guided movements to attenuate the impact of eye and head misalignment. Our observations provide indications for rehabilitation procedures and for the design of upcoming retinal prostheses. (ClinicalTrials.gov number, NCT00407602.).
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Affiliation(s)
- Norman Sabbah
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France
| | - Colas N Authié
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France
| | - Nicolae Sanda
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France
| | - Saddek Mohand-Said
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France
| | - Avinoam B Safran
- Sorbonne Universités, UPMC Université Paris 06, UMR S968, Institut de la Vision, Paris, France Department of Clinical Neurosciences, Geneva University School of Medicine, Geneva, Switzerland
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Safran AB, Sanda N, Sahel JA. A neurological disorder presumably underlies painter Francis Bacon distorted world depiction. Front Hum Neurosci 2014; 8:581. [PMID: 25221491 PMCID: PMC4148635 DOI: 10.3389/fnhum.2014.00581] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 07/14/2014] [Indexed: 11/13/2022] Open
Affiliation(s)
- Avinoam B Safran
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, INSERM, U968, CNRS, UMR_7210 Paris, France ; Neurosciences, Geneva University School of Medecine Geneva, Switzerland
| | - Nicolae Sanda
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, INSERM, U968, CNRS, UMR_7210 Paris, France ; Neurology Department, Hôpital Foch Paris, France
| | - José-Alain Sahel
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, INSERM, U968, CNRS, UMR_7210 Paris, France
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Humayun MS, Dorn JD, da Cruz L, Dagnelie G, Sahel JA, Stanga PE, Cideciyan AV, Duncan JL, Eliott D, Filley E, Ho AC, Santos A, Safran AB, Arditi A, Del Priore LV, Greenberg RJ. Interim results from the international trial of Second Sight's visual prosthesis. Ophthalmology 2012; 119:779-88. [PMID: 22244176 DOI: 10.1016/j.ophtha.2011.09.028] [Citation(s) in RCA: 522] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 11/25/2022] Open
Abstract
PURPOSE This study evaluated the Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA) in blind subjects with severe outer retinal degeneration. DESIGN Single-arm, prospective, multicenter clinical trial. PARTICIPANTS Thirty subjects were enrolled in the United States and Europe between June 6, 2007, and August 11, 2009. All subjects were followed up for a minimum of 6 months and up to 2.7 years. METHODS The electronic stimulator and antenna of the implant were sutured onto the sclera using an encircling silicone band. Next, a pars plana vitrectomy was performed, and the electrode array and cable were introduced into the eye via a pars plana sclerotomy. The microelectrode array then was tacked to the epiretinal surface. MAIN OUTCOME MEASURES The primary safety end points for the trial were the number, severity, and relation of adverse events. Principal performance end points were assessments of visual function as well as performance on orientation and mobility tasks. RESULTS Subjects performed statistically better with the system on versus off in the following tasks: object localization (96% of subjects), motion discrimination (57%), and discrimination of oriented gratings (23%). The best recorded visual acuity to date is 20/1260. Subjects' mean performance on orientation and mobility tasks was significantly better when the system was on versus off. Seventy percent of the patients did not have any serious adverse events (SAEs). The most common SAE reported was either conjunctival erosion or dehiscence over the extraocular implant and was treated successfully in all subjects except in one, who required explantation of the device without further complications. CONCLUSIONS The long-term safety results of Second Sight's retinal prosthesis system are acceptable, and most subjects with profound visual loss perform better on visual tasks with system than without it.
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Affiliation(s)
- Mark S Humayun
- Doheny Eye Institute, University of Southern California, Los Angeles, California, USA.
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Aliferis K, Petropoulos IK, Farpour B, Matter MA, Safran AB. Should central serous chorioretinopathy be added to the list of ocular side effects of phosphodiesterase 5 inhibitors? ACTA ACUST UNITED AC 2011; 227:85-9. [PMID: 22156704 DOI: 10.1159/000333824] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 09/25/2011] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Rare cases of central serous chorioretinopathy (CSC) associated with the intake of sildenafil citrate have been reported, although CSC is not included in the list of phosphodiesterase 5 (PDE5) inhibitor side effects. MATERIALS AND METHODS We present a review of the literature and 2 cases of CSC in 2 men taking PDE5 inhibitors (vardenafil and tadalafil) for erectile dysfunction. In both cases chorioretinopathy appeared after intake of the inhibitor, resolved once the latter was discontinued, reappeared when the inhibitor was restarted and resolved once again after the inhibitor had been discontinued for the second time. DISCUSSION PDE5 inhibitors used for male erectile dysfunction have been associated with ocular side effects including lid edema, hyposphagma, photophobia, mydriasis, dyschromatopsia, and nonarteritic anterior ischemic optic neuropathy. CSC was previously described in patients taking sildenafil citrate. Very recently, a case of CSC after tadalafil intake was reported. The relevant literature is reviewed and possible pathophysiologic mechanisms are discussed. CONCLUSION The 2 presented cases of CSC after intake of vardenafil or tadalafil with positive dechallenge, rechallenge and second dechallenge reactions provide important arguments for considering CSC as a rare PDE5 inhibitor class-specific side effect.
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Affiliation(s)
- K Aliferis
- Department of Ophthalmology, Geneva University Hospital, Geneva, Switzerland
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Goldschmidt M, Déruaz A, Lorincz EN, Whatham AR, Mermoud C, Safran AB. Reading strategies in Stargardt's disease with foveal sparing. BMC Res Notes 2010; 3:15. [PMID: 20180995 PMCID: PMC2843730 DOI: 10.1186/1756-0500-3-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Accepted: 01/22/2010] [Indexed: 11/25/2022] Open
Abstract
Background Subjects with a ring scotoma can use two retinal loci, a foveal and a peripheral, for reading. Our aim was to investigate the relative use of both retinal loci as a function of the spared foveal area size and the spatial resolution at both retinal loci. Findings Two patients with Stargardt's disease and ring scotomas read through a scanning laser ophthalmoscope a series of letters and words at various character sizes. The number of fixations made using each retinal locus was quantified. The relative use of each retinal locus depended on character size of the stimulus. Both patients used exclusively the eccentric retinal locus to read words of large character sizes. At small character sizes, the central retinal locus was predominantly used. For reading letters or words, once foveal fixation was used, patients did not shift back to the eccentric retinal locus. When spatial resolution allowed deciphering at both the eccentric and the central areas, patients consistently fixated with the eccentric retinal locus. Conclusions Spatial resolution at the eccentric locus appears as a determinant factor to select the retinal area for reading. Reading strategies in patients with Stargardt's disease and a ring scotoma demonstrate a pattern of coordination of both eccentric and central retinal loci, reflecting a high degree of adaptation.
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Affiliation(s)
- Mira Goldschmidt
- Ophthalmology Clinic, Department of Clinical Neurosciences, Geneva University Hospitals, Alcide-Jentzer 22, 1211 Geneva 14, Switzerland.
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Wild JM, Chiron C, Ahn H, Baulac M, Bursztyn J, Gandolfo E, Goldberg I, Goñi FJ, Mercier F, Nordmann JP, Safran AB, Schiefer U, Perucca E. Visual field loss in patients with refractory partial epilepsy treated with vigabatrin: final results from an open-label, observational, multicentre study. CNS Drugs 2009; 23:965-82. [PMID: 19845417 DOI: 10.2165/11317650-000000000-00000] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND Use of the antiepileptic drug vigabatrin is associated with an elevated risk of visual field loss. OBJECTIVE To determine the frequency of, and risk factors for, vigabatrin-attributed visual field loss (VAVFL) in the setting of a large-scale, multinational, prospective, observational study. STUDY DESIGN A comparative, open-label, parallel-group, multicentre study. SETTING Hospital outpatient clinics at 46 centres in five countries. PATIENTS 734 patients with refractory partial epilepsy, divided into three groups and stratified by age (8-12 years; >12 years) and exposure to vigabatrin. Group I comprised patients treated with vigabatrin for > or =6 months. Group II comprised patients previously treated with vigabatrin for > or =6 months who had withdrawn from the drug for > or =6 months. Group III comprised patients never treated with vigabatrin. Patients underwent perimetry at either 4- or 6-month intervals, for up to 36 months. Visual field outcome was evaluated masked to drug exposure. INTERVENTION Perimetry. MAIN OUTCOME MEASURE The visual field outcome at each of four analysis points: (i) at enrolment (i.e. baseline, all patients); (ii) for patients exhibiting a conclusive outcome at the initial visual field examination; (iii) for patients exhibiting at least one conclusive outcome to the visual field examinations; and (iv) at the last conclusive outcome to the visual field examinations. RESULTS Of the 734 patients, 524 yielded one or more conclusive visual field examinations. For Group I, the frequency of VAVFL at the last conclusive examination was 10/38 (26.3%) for those aged 8-12 years and 65/150 (43.3%) for those aged >12 years. For Group II, the respective frequencies were 7/47 (14.9%) and 37/151 (24.5%). One case resembling VAVFL was present amongst the 186 patients in Group III at the last conclusive examination. The frequency of VAVFL in Groups I and II combined was 20.0% for those aged 8-12 years and 33.9% for those aged >12 years. VAVFL was associated with duration of vigabatrin therapy (odds ratio [OR] up to 15.2; 95% CI 4.4, 51.7), mean daily dose of vigabatrin (OR up to 26.4; 95% CI 2.4, 291.7) and male gender (OR 2.51; 95% CI 1.5, 4.1). VAVFL was more frequently detected with static than with kinetic perimetry (OR up to 0.43; 95% CI 0.24, 0.75). CONCLUSIONS Since the probability of VAVFL is positively associated with treatment duration, careful assessment of the risk-benefit ratio of continuing treatment with vigabatrin is recommended in patients currently receiving this drug. All patients continuing to receive vigabatrin should undergo visual field examination at least every 6 months for the duration of treatment. We recommend two-level (three-zone), gradient-adapted, suprathreshold static perimetry of the peripheral field together with threshold perimetry of the central field out to 30 degrees from fixation. The frequency of ophthalmological and perimetric examinations should be increased in the presence of VAVFL.
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Affiliation(s)
- John M Wild
- Cardiff School of Optometry and Vision Sciences, Cardiff University, Cardiff CF24 4LU, Wales, UK.
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Laffi GL, Guidi SG, Meduri R, Scorolli L, Golfieri R, Eusebi V, Safran AB. Cholesteatoma of the sphenoid sinus presenting as painful optic neuropathy. Neuroophthalmology 2009. [DOI: 10.3109/01658109409024058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Mendrinos E, Pilly B, Baglivo E, Donati G, Safran AB, Pournaras CJ. Chorioretinal anastomosis as a rare complication of radiation retinopathy. Acta Ophthalmol 2009; 87:473-5. [PMID: 18652579 DOI: 10.1111/j.1755-3768.2008.01280.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kaeser PF, Rossillion B, Menache Starobinski C, Korff C, Safran AB. Optic disc dysplasia in cerebral gray matter heterotopias: a valuable clinical clue. Klin Monbl Augenheilkd 2009; 226:370-1. [PMID: 19384808 DOI: 10.1055/s-0028-1109282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- P-F Kaeser
- Service d'ophtalmologie, Hôpitaux Universitaires de Genève, Switzerland
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Mégevand P, Pilly B, Delavelle J, Tajouri N, Safran AB, Landis T, Lüscher C. Sixth cranial nerve palsy and contralateral hemiparesis (Raymond's syndrome) sparing the face. J Neurol 2009; 256:1017-8. [PMID: 19252793 DOI: 10.1007/s00415-009-5041-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Revised: 01/06/2009] [Accepted: 01/28/2009] [Indexed: 11/25/2022]
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Zhao C, Lu S, Truffert A, Tajouri N, Zhao K, Mateo Montoya A, Dosso A, Landis T, Safran AB. Corneal nerves alterations in various types of systemic polyneuropathy, identified by in vivo confocal microscopy. Klin Monbl Augenheilkd 2008; 225:413-7. [PMID: 18454383 DOI: 10.1055/s-2008-1027259] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND In vivo confocal microscopy (IVCM) is a newly developed application to assess corneal nerve morphology. The purpose of the study is to evaluate the role of IVCM in the assessment of various types of polyneuropathy, and to define alterations of corneal nerves in such conditions. PATIENTS AND METHODS Eighteen patients with various types of polyneuropathy were characterized by clinical neurological and ophthalmic examinations, as well as by electroneuromyography (ENMG). Full thickness IVCM of corneal nerves was carried out on all patients and 15 age-matched eyes using Heidelberg Retina Tomograph II (HRT II). The subbasal nerve plexus were statistically analysed regarding long nerve fiber density, nerve branch density, nerve thickness, nerve bead number and nerve tortuosity. RESULTS In subbasal nerve plexus, the following three parameters were significantly reduced in patients with polyneuropathy compared to controls: long nerve fibre density (p < 0.01), nerve branch density (p < 0.001), and nerve bead number (p = 0.001). In addition, the average grade of nerve tortuosity was 2.87 +/- 0.97 in the polyneuropathic group and 1.17 +/- 0.68 in the control group (p < 0.0001). CONCLUSIONS IVCM allows a non-invasive, in vivo study of corneal nerves with high resolution. It therefore appears invaluable in clinical investigations. IVCM appears to be valuable in a large variety of polyneuropathic conditions.
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Affiliation(s)
- C Zhao
- Ophthalmology Clinic, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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Abstract
PURPOSE The risk factors for visual field loss attributable to vigabatrin (VAVFL) are equivocal. This multinational, prospective, observational study aimed to clarify the principal/major factors for VAVFL. METHODS Interim analysis of three groups with refractory partial epilepsy, stratified by age (8-12 years; >12 years) and exposure to vigabatrin (VGB). Group I comprised participants treated with VGB for >or=6 months, Group II participants previously treated with VGB for >or=6 months who had discontinued the drug for >or=6 months and Group III those never treated with VGB. Perimetry was undertaken at least every six months, for up to 36 months; results were evaluated masked to drug exposure. RESULTS Based upon 563 participants in the locked data set, 432 yielded one or more Conclusive visual field examinations. For Group I, the frequency of VAVFL at the last Conclusive examination was 10/32 (31.2%) for those aged 8-12 years and 52/125 (41.6%) for those aged >12 years. For Group II, the proportions were 4/39 (10.3%) and 31/129 (24.0%). No cases resembling VAVFL manifested in Group III. VAVFL was associated with duration of VGB therapy (Odds ratio [OR] 14.2; 95% CI 5.0 to 40.5); mean dose of VGB (OR 8.5; 95% CI 2.2 to 33.2); and male gender (OR 2.1; 95% CI 1.2 to 3.7). VAVFL was more common with static than kinetic perimetry (OR 2.3, 95% CI 1.3 to 4.2). CONCLUSIONS The therapeutic benefit of VGB is counteracted by the progressive accrual of the risk of VAVFL with continued exposure and with increase in mean dose.
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Affiliation(s)
- John M Wild
- Cardiff School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
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Blanke O, Brooks A, Mercier M, Spinelli L, Adriani M, Lavanchy L, Safran AB, Landis T. Distinct mechanisms of form-from-motion perception in human extrastriate cortex. Neuropsychologia 2007; 45:644-53. [PMID: 17049953 DOI: 10.1016/j.neuropsychologia.2006.07.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 07/13/2006] [Accepted: 07/23/2006] [Indexed: 10/24/2022]
Abstract
The exquisite sensitivity of the human visual system to form-from-motion (FfM) cues is well documented. However, identifying the neural correlates of this sensitivity has proven difficult, particularly determining the respective contributions of different motion areas in extrastriate visual cortex. Here we measured visual FfM perception and more elementary visual motion (VM) perception in a group of 32 patients suffering from acute posterior brain damage, and performed MRI-based lesion analysis. Our results suggest that severe FfM perception deficits without an associated deficit of VM perception are due to damage to ventral occipito-temporal cortex (VOT), whereas associated deficits of FfM and VM perception are due to damage either in proximity to area MT+/V5 or an area including lateral occipital complex (LOC) and VOT. These data suggest the existence of at least three functionally and anatomically distinct regions in human visual cortex that process FfM signals.
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Affiliation(s)
- O Blanke
- Laboratory of Cognitive Neuroscience, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Déruaz A, Goldschmidt M, Whatham AR, Mermoud C, Lorincz EN, Schnider A, Safran AB. A technique to train new oculomotor behavior in patients with central macular scotomas during reading related tasks using scanning laser ophthalmoscopy: immediate functional benefits and gains retention. BMC Ophthalmol 2006; 6:35. [PMID: 17123448 PMCID: PMC1693567 DOI: 10.1186/1471-2415-6-35] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 11/23/2006] [Indexed: 11/25/2022] Open
Abstract
Background Reading with a central scotoma involves the use of preferred retinal loci (PRLs) that enable both letter resolution and global viewing of word. Spontaneously developed PRLs however often privilege spatial resolution and, as a result, visual span is commonly limited by the position of the scotoma. In this study we designed and performed the pilot trial of a training procedure aimed at modifying oculomotor behavior in subjects with central field loss. We use an additional fixation point which, when combined with the initial PRL, allows the fulfillment of both letter resolution and global viewing of words. Methods The training procedure comprises ten training sessions conducted with the scanning laser ophthalmoscope (SLO). Subjects have to read single letters and isolated words varying in length, by combining the use of their initial PRL with the one of an examiner's selected trained retinal locus (TRL). We enrolled five subjects to test for the feasibility of the training technique. They showed stable maculopathy and persisting major reading difficulties despite previous orthoptic rehabilitation. We evaluated ETDRS visual acuity, threshold character size for single letters and isolated words, accuracy for paragraphed text reading and reading strategies before, immediately after SLO training, and three months later. Results Training the use of multiple PRLs in patients with central field loss is feasible and contributes to adapt oculomotor strategies during reading related tasks. Immediately after SLO training subjects used in combination with their initial PRL the examiner's selected TRL and other newly self-selected PRLs. Training gains were also reflected in ETDRS acuity, threshold character size for words of different lengths and in paragraphed text reading. Interestingly, subjects benefited variously from the training procedure and gains were retained differently as a function of word length. Conclusion We designed a new procedure for training patients with central field loss using scanning laser ophthalmoscopy. Our initial results on the acquisition of newly self-selected PRLs and the development of new oculomotor behaviors suggest that the procedure aiming primarily at developing an examiner's selected TRL might have initiated a more global functional adaptation process.
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Affiliation(s)
- Anouk Déruaz
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
- Perception and Eye Movement Laboratory, Department of Neurology and Department of Clinical Research, University of Bern, Inselspital, Switzerland
| | - Mira Goldschmidt
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
| | - Andrew R Whatham
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
| | - Christophe Mermoud
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
| | - Erika N Lorincz
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
| | - Armin Schnider
- Division of Rehabilitation, Department of Clinical Neurosciences and Dermatology, Geneva University Hospital, Switzerland
| | - Avinoam B Safran
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Switzerland
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Salzmann J, Linderholm OP, Guyomard JL, Paques M, Simonutti M, Lecchi M, Sommerhalder J, Dubus E, Pelizzone M, Bertrand D, Sahel J, Renaud P, Safran AB, Picaud S. Subretinal electrode implantation in the P23H rat for chronic stimulations. Br J Ophthalmol 2006; 90:1183-7. [PMID: 16754649 PMCID: PMC1857388 DOI: 10.1136/bjo.2005.089110] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND In age related macular degeneration and inherited dystrophies, preservation of retinal ganglion cells has been demonstrated. This finding has led to the development of various models of subretinal or epiretinal implant in order to restore vision. This study addresses the development of a polyimide subretinal electrode platform in the dystrophic P23H rat in vivo. METHODS A technique was developed for implanting a subretinal electrode into the subretinal space and stabilising the distal extremity of the cabling on the rat cranium in order to allow future electrical stimulations of the retina. RESULTS In vivo imaging of the retina with the scanning laser ophthalmoscope demonstrated reabsorption of the surgically induced retinal detachment and the absence of major tissue reactions. These in vivo observations were confirmed by retinal histology. The extraocular fixation system on the rat cranium was effective in stabilising the distal connector for in vivo stimulation. CONCLUSION This study demonstrates that a retinal implant can be introduced into the subretinal space of a dystrophic rat with a stable external connection for repeatable electrical measurements and stimulation. This in vivo model should therefore allow us to evaluate the safety and efficacy of electrical stimulations on dystrophic retina.
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Affiliation(s)
- J Salzmann
- Service d'Opthalmologie Hôpitaux Universitaires de Genève, Switzerland
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Déruaz A, Goldschmidt M, Mermoud C, Whatham AR, Safran AB. The relationship between word length and threshold character size in patients with central scotoma and eccentric fixation. Graefes Arch Clin Exp Ophthalmol 2006; 244:570-6. [PMID: 16163495 DOI: 10.1007/s00417-005-0111-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2005] [Revised: 07/14/2005] [Accepted: 08/03/2005] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Understanding limitations on text reading with eccentric fixation is of major concern in low vision research. Our objective was to determine, in patients with a central scotoma, whether threshold character size is similar for different word lengths and paragraphed texts. METHODS In 19 patients, we retrospectively analyzed the relationship between minimum readable character size for isolated words and text. Isolated letters, two, five, and ten-letter words and a paragraphed text were presented randomly through a scanning laser ophthalmoscope in eight different character sizes. RESULTS Threshold character size varied according to the text stimulus (p<0.05). Threshold character sizes for single letters and two-letter words were matched (p>0.99), as were those for five-letter words, ten-letter words, and paragraphed text (p>0.99). Threshold character size for single letters and two-letter words was significantly lower than that measured with other text stimuli. DISCUSSION Reading performance is influenced by a variety of factors such as crowding, contextual effects, visual span, degree of oculomotor adaptation needed, and frequency of a defined word. Globally, when reading with a central scotoma, it appears that within word characteristics have more impact than inter-word parameters on threshold character size.
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Affiliation(s)
- Anouk Déruaz
- Clinique d'Ophtalmologie, Hôpitaux Universitaires de Genève, 22, Alcide-Jentzer, 1211, Genève 14, Switzerland.
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Abstract
PURPOSE Adaptation to eccentric viewing in subjects with a central scotoma remains poorly understood. The purpose of this study was to analyze the adaptation stages of oculomotor control to forced eccentric reading in normal subjects. METHODS Three normal adults (25.7 +/- 3.8 years of age) were trained to read full-page texts using a restricted 10 degrees x 7 degrees viewing window stabilized at 15 degrees eccentricity (lower visual field). Gaze position was recorded throughout the training period (1 hour per day for approximately 6 weeks). RESULTS In the first sessions, eye movements appeared inappropriate for reading, mainly consisting of reflexive vertical (foveating) saccades. In early adaptation phases, both vertical saccade count and amplitude dramatically decreased. Horizontal saccade frequency increased in the first experimental sessions, then slowly decreased after 7 to 15 sessions. Amplitude of horizontal saccades increased with training. Gradually, accurate line jumps appeared, the proportion of progressive saccades increased, and the proportion of regressive saccades decreased. At the end of the learning process, eye movements mainly consisted of horizontal progressions, line jumps, and a few horizontal regressions. CONCLUSIONS Two main adaptation phases were distinguished: a "faster" vertical process aimed at suppressing reflexive foveation and a "slower" restructuring of the horizontal eye movement pattern. The vertical phase consisted of a rapid reduction in the number of vertical saccades and a rapid but more progressive adjustment of remaining vertical saccades. The horizontal phase involved the amplitude adjustment of horizontal saccades (mainly progressions) to the text presented and the reduction of regressions required.
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Affiliation(s)
- Angélica Pérez Fornos
- Ophthalmology Clinic, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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Abstract
Determining causes of poor reading ability is an important step in trying to ameliorate reading performance in low-vision patients. One important parameter is word acuity. The principal aim of the current study is to develop a method to reliably measure acuities for isolated lowercase letters and words of differing length that can be used to test low-vision patients. Using isolated stimuli means that testing is relatively free of potential crowding and/or distracting attentional effects from surrounding words, it is unambiguous which stimulus subjects are trying to read and response times can be recorded for each stimulus. Across a series of experiments, subjects with normal vision were asked to read isolated lowercase single letters and lowercase words of 4, 7 and 10 letters, in separate tests. Acuities for uppercase Sloan letters were also measured to provide a reference, as they are commonly used to measure visual acuity. Each test was based upon the design principles and scoring procedures used in the Bailey-Lovie and ETDRS charts. Acuities for uppercase Sloan letters were found to be equivalent whether measured using ETDRS charts or the computer-based method. Measurement of acuities for lowercase single letters and lowercase words of 4, 7 and 10 letters had a reliability that was no worse than acuities for uppercase Sloan letters. Lowercase word acuities were essentially independent of word length. Acuities for single lowercase letters and lowercase words were slightly better than uppercase Sloan letters acuity. Optimal processing of lowercase single letters and 4-, 7- and 10-letter words occurred at character sizes that were at least 0.2-0.40 log MAR above acuity threshold, i.e. between 1.5 and 3 times threshold acuity for that particular stimulus. In general, critical character sizes appear similar across word lengths as progressive increases or decreases in these values were not observed as a function of the number of letters in the stimulus. We conclude that a computer-based method of stimulus presentation can be used to obtain highly repeatable measures of acuity for lowercase single letters and lowercase words in normal vision.
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Affiliation(s)
- Andrew R Whatham
- Department of Clinical Neurosciences and Dermatology, Ophthalmology Clinic, Neuro-Ophthalmology Unit, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
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Fornos AP, Sommerhalder J, Rappaz B, Safran AB, Pelizzone M. Simulation of Artificial Vision, III: Do the Spatial or Temporal Characteristics of Stimulus Pixelization Really Matter? ACTA ACUST UNITED AC 2005; 46:3906-12. [PMID: 16186381 DOI: 10.1167/iovs.04-1173] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE In preceding studies, simulations of artificial vision were used to determine the basic parameters for visual prostheses to restore useful reading abilities. These simulations were based on a simplified procedure to reduce stimuli information content by preprocessing images with a block-averaging algorithm (square pixelization). In the present study, how such a simplified algorithm affects reading performance was examined. METHODS Five to six volunteers with normal vision were asked to read full pages of text with a 10 degrees x 7 degrees viewing window stabilized in central vision. In a first experiment, reading performance with off-line and real-time square pixelizations was compared at different resolutions. In a second experiment, off-line square pixelization was compared with off-line Gaussian pixelization with various degrees of overlap. In a third experiment, real-time square pixelization was compared with real-time Gaussian pixelization. RESULTS Results from the first experiment showed that real-time square pixelization required approximately 30% less information (pixels) than its off-line counterpart. Results from the second experiment, using off-line processing, revealed a restricted range of Gaussian widths for which performances were equivalent or significantly better than that obtained with square pixelization. The third experiment demonstrated, however, that reading performances were similar in both real-time pixelization conditions. CONCLUSIONS This study reveals that real-time stimulus pixelization favors reading performance. Performance gains were moderate, however, and did not allow for a significant (e.g., twofold) reduction of the minimum resolution (400-500 pixels) needed to achieve useful reading abilities.
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Affiliation(s)
- Angélica Pérez Fornos
- Ophthalmology Clinic, Department of Clinical Neurosciences, Geneva University Hospitals, Switzerland
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Seghier ML, Lazeyras F, Zimine S, Saudan-Frei S, Safran AB, Huppi PS. Visual recovery after perinatal stroke evidenced by functional and diffusion MRI: case report. BMC Neurol 2005; 5:17. [PMID: 16185359 PMCID: PMC1249577 DOI: 10.1186/1471-2377-5-17] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 09/26/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND After perinatal brain injury, clinico-anatomic correlations of functional deficits and brain plasticity remain difficult to evaluate clinically in the young infant. Thus, new non-invasive methods capable of early functional diagnosis are needed in young infants. CASE PRESENTATION The visual system recovery in an infant with perinatal stroke is assessed by combining diffusion tensor imaging (DTI) and event-related functional MRI (ER-fMRI). All experiments were done at 1.5T. A first DTI experiment was performed at 12 months of age. At 20 months of age, a second DTI experiment was performed and combined with an ER-fMRI experiment with visual stimuli (2 Hz visual flash). At 20 months of age, ER-fMRI showed significant negative activation in the visual cortex of the injured left hemisphere that was not previously observed in the same infant. DTI maps suggest recovery of the optic radiation in the vicinity of the lesion. Optic radiations in the injured hemisphere are more prominent in DTI at 20 months of age than in DTI at 12 months of age. CONCLUSION Our data indicate that functional cortical recovery is supported by structural modifications that concern major pathways of the visual system. These neuroimaging findings might contribute to elaborate a pertinent strategy in terms of diagnosis and rehabilitation.
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Affiliation(s)
- Mohamed L Seghier
- Department of Radiology, Geneva University Hospitals, Micheli-du-Crest 24, 1211 Geneva, Switzerland
- Laboratory for Neurology and Imaging of Cognition, Departments of Neurosciences, University of Geneva, Michel-Servet 1, Geneva 1211, Switzerland
| | - François Lazeyras
- Department of Radiology, Geneva University Hospitals, Micheli-du-Crest 24, 1211 Geneva, Switzerland
| | - Slava Zimine
- Department of Radiology, Geneva University Hospitals, Micheli-du-Crest 24, 1211 Geneva, Switzerland
| | - Sonja Saudan-Frei
- Department of Anesthesiology, Geneva University Hospitals, Micheli-du-Crest 24, 1211 Geneva, Switzerland
| | - Avinoam B Safran
- Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Geneva, Switzerland
| | - Petra S Huppi
- Department of Neurology, Children's Hospital, Harvard Medical School, Boston, USA
- Department of Pediatrics, Children's Hospital of Geneva, 6 rue Willy-Donzé, 1211 Geneva, Switzerland
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Lecchi M, McIntosh JM, Bertrand S, Safran AB, Bertrand D. Functional properties of neuronal nicotinic acetylcholine receptors in the chick retina during development. Eur J Neurosci 2005; 21:3182-8. [PMID: 15978026 DOI: 10.1111/j.1460-9568.2005.04150.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Acetylcholine (ACh) has been recognized for a long time as a major neurotransmitter in the retina, however, little is known about the contribution of acetylcholine receptors in synaptic processing. Moreover, even less information is available concerning their role during development. To address this question further, we examined the physiological and pharmacological properties of neuronal nicotinic acetylcholine receptors (nAChRs) in retinal ganglion cells from embryonic (E) 12-18-day-old Leghorn chicks. Patch-clamp recordings in whole-cell configuration revealed that at E12 approximately 21% of the ganglion cells responded to acetylcholine pulses with inward currents. The number of responsive cells progressively increased to 57% at E15 to reach up to 15 positive cells out of 15 cells tested at E18. Acetylcholine-evoked responses could be subdivided, according to their time course, into fast and slowly desensitizing. Taking advantage of the selectivity of the frog toxin epibatidine (Epi), that preferentially activates heteromeric neuronal nicotinic acetylcholine receptors, we compared the currents evoked by this toxin vs. the effects of acetylcholine. A further characterization of the receptor diversity during development was to assess their sensitivity to the alpha-conotoxin MII (alpha-CTX-MII), which has been shown to preferentially block alpha6- and alpha3beta2-containing receptors. These data demonstrate that ganglion cells of the chick retina express multiple receptor subtypes that progressively develop as a function of retina maturation.
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Affiliation(s)
- Marzia Lecchi
- Department of Neurosciences, Faculty of Medicine, CMU, 1 rue Michel Servet, CH-1211 Geneva, Switzerland.
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Dang Burgener NP, Baglivo E, Harbarth S, Sahabo C, Pittet D, Safran AB. Pasteurella multocida endophthalmitis: case report and review of the literature. Klin Monbl Augenheilkd 2005; 222:231-3. [PMID: 15785987 DOI: 10.1055/s-2005-857968] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Postoperative bacterial endophthalmitis is caused by the patient's endogenous flora in most cases (80 %). Pasteurella multocida (PM) is a Gram-negative coccobacillus found in the upper respiratory tract of dogs and cats and is very rarely implicated in postoperative endophthalmitis. HISTORY AND SIGNS We describe a case of PM endophthalmitis that developed after cataract surgery. THERAPY AND OUTCOME Cultures of both the conjunctiva and the aqueous humor were positive for PM. Topical, intravitreous and intravenous antibiotics were administered. Despite treatment, the outcome was unfavourable and complicated by a corneal perforation. CONCLUSIONS The prognosis of postoperative PM endophthalmitis remains poor, despite adequate treatment of the infection. A history of recent pet exposure should alert physicians to this possible aetiological factor.
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Affiliation(s)
- N P Dang Burgener
- Clinique d'Ophtalmologie, Hôpitaux Universitaires de Genève, Geneva, Switzerland
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34
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Oueghlani E, Baglivo E, Durakovic O, Safran AB. Varicella-Zoster Virus Retinitis: Successful Evolution with a Combination of Antiviral Therapies. Klin Monbl Augenheilkd 2005; 222:264-6. [PMID: 15785997 DOI: 10.1055/s-2005-857980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND We present the description of a successful outcome in a case of varicella-zoster virus (VZV) acute retinal necrosis (ARN). HISTORY AND SIGNS A healthy 40-year-old patient was admitted for a VZV retinitis. THERAPY AND OUTCOME 10 days after the onset of intravenous (i. v.) acyclovir treatment, new small peripheral retinal necrotic lesions appeared in the right eye. A viral resistance was suspected and the acyclovir therapy was optimised with i. v. foscarnet combined with 2 intravitreal injections of ganciclovir. The outcome was favourable with a final vision of 1.0 after a follow-up of 30 months. No systemic or local complications were observed. CONCLUSIONS VZV ARN is a severe infection with a poor prognosis. This case demonstrates that combination of antiviral therapies given intravenously (acyclovir + foscarnet) and in the vitreous (ganciclovir) may be safe and efficacious in the management of necrotising herpetic retinopathies affecting immunocompetent patients.
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Affiliation(s)
- E Oueghlani
- Clinique d'Ophtalmologie, Hôpitaux Universitaires de Genève, Geneva, Switzerland
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35
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Abstract
The authors report a family affected by multiple daily episodes of transient visual loss, elicited repetitive daily blindness (ERDB); the onset was early in life, and the disease followed a benign course. ERDB is associated with childhood epilepsy and familial hemiplegic migraine, apparently segregating as a monogenic, autosomal dominant condition with variable expression. Genetic linkage to CACNA1A was excluded.
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Varsori M, Perez-Fornos A, Safran AB, Whatham AR. Development of a viewing strategy during adaptation to an artificial central scotoma. Vision Res 2004; 44:2691-705. [PMID: 15358064 DOI: 10.1016/j.visres.2004.05.027] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2003] [Revised: 05/26/2004] [Indexed: 10/26/2022]
Abstract
Although many individuals with a central scotoma develop eccentric fixation most often beneath or left of the scotoma, little is known about how they come to develop a particular viewing strategy. We investigated this by asking eight subjects with normal vision to read isolated letters, words and text passages while an artificial scotoma covered a central portion of the visual field. We quantified viewing strategy and analysed changes in their viewing behaviour over 8-10 sessions within a two-week period. Subjects read while either a horizontal (n=4) or vertical bar scotoma (n=4), 10 degrees wide, covered the entire horizontal or vertical meridian of the stimulus field. For the horizontal scotoma group: (1) there was an increasing preference to use the inferior visual field for isolated letters/words and text passages, which was essentially complete within the test period; (2) the superior visual field was preferred when reading letters/words initially presented in upper visual space and the inferior visual field when reading letters/words initially presented in lower visual space; (3) in general, variation in viewing strategy according to stimulus position diminished over the sessions for all stimuli. For the vertical scotoma group: (1) two subjects used the left and right visual fields in approximately equal proportion to view isolated letters/words, one subject showed a weak preference to use the left visual field and one subject developed a strong preference for using the right visual field; (2) the text passages could be read with combined use of left and right visual fields in a specific manner; (3) the left visual field was preferred to view stimuli initially presented in left visual space while the right visual field was preferred for words initially presented in right visual space. This effect diminished across sessions. Overall, these findings indicate that (1) a specific viewing strategy can be developed through as little as 5 hours of reading experience without guided training; (2) two distinctly separate retinal areas can be used in an integrated manner during reading; (4) stimulus position in visual space can influence viewing strategy; (5) in general, reading encourages a preference for the inferior over the superior visual field, but not the left over right visual field. Letter/word/text recognition and reading speeds increased progressively across sessions, even after scotoma lateralisation appeared stabilised suggesting that multiple mechanism are involved in adaptive changes.
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Affiliation(s)
- Michael Varsori
- Neuro-Ophthalmology Unit, Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Rue Micheli-du-Crest 1211, Geneva 14, Switzerland
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Sommerhalder J, Rappaz B, de Haller R, Fornos AP, Safran AB, Pelizzone M. Simulation of artificial vision: II. Eccentric reading of full-page text and the learning of this task. Vision Res 2004; 44:1693-706. [PMID: 15136004 DOI: 10.1016/j.visres.2004.01.017] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2003] [Revised: 01/13/2004] [Indexed: 11/26/2022]
Abstract
Reading of isolated words in conditions mimicking artificial vision has been found to be a difficult but feasible task. In particular at relatively high eccentricities, a significant adaptation process was required to reach optimal performances [Vision Res. 43 (2003) 269]. The present study addressed the task of full-page reading, including page navigation under control of subject's own eye movements. Conditions of artificial vision mimicking a retinal implant were simulated by projecting stimuli with reduced information content (lines of pixelised text) onto a restricted and eccentric area of the retina. Three subjects, naïve to the task, were trained for almost two months (about 1 h/day) to read full-page texts. Subjects had to use their own eye movements to displace a 10 degrees x 7 degrees viewing window, stabilised at 15 degrees eccentricity in their lower visual field. Initial reading scores were very low for two subjects (about 13% correctly read words), and astonishingly high for the third subject (86% correctly read words). However, all of them significantly improved their performance with time, reaching close to perfect reading scores (ranging from 86% to 98% correct) at the end of the training process. Reading rates were as low as 1-5 words/min at the beginning of the experiment and increased significantly with time to 14-28 words/min. Qualitative text understanding was also estimated. We observed that reading scores of at least 85% correct were necessary to achieve 'good' text understanding. Gaze position recordings, made during the experimental sessions, demonstrated that the control of eye movements, especially the suppression of reflexive vertical saccades, constituted an important part of the overall adaptive learning process. Taken together, these results suggest that retinal implants might restore full-page text reading abilities to blind patients. About 600 stimulation contacts, distributed on an implant surface of 3 x 2 mm2, appear to be a minimum to allow for useful reading performance. A significant learning process will however be required to reach optimal performance with such devices, especially if they have to be placed outside the foveal area.
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Affiliation(s)
- Jörg Sommerhalder
- Ophthalmology Clinic, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
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Zaninetti M, Safran AB. [The value of multifocal ERG in diagnosis of discrete macular dystrophies]. Klin Monbl Augenheilkd 2004; 221:379-82. [PMID: 15162285 DOI: 10.1055/s-2004-812875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Multifocal ERG is being extensively applied to numerous retinal disorders. It has gained particular clinical value in retinal disorders developing without morphological alterations. PATIENTS AND METHODS We investigated a series of 4 patients, aged 10, 18, 29, and 49 years, respectively. When examined, they complained of photophobia and slowly progressive bilateral loss of vision, visual acuity ranging from 0.7 to 0.1. RESULTS Ophthalmoscopic examination showed no or minimal alterations such as subtle granular changes in the fovea. Photopic-scotopic full-field ERG was normal. Multifocal ERG, in contrast, showed markedly reduced signal amplitudes within the central 10 degrees. CONCLUSIONS Based on the results of multifocal ERG, we were able in each case to consider with a high degree of probability the diagnosis of progressive foveal cone dystrophy. This is to emphasize the sensitivity of multifocal ERG in disorders affecting primarily the macula, without morphological changes, as cone (-rod) dystrophy, early Stargardt dystrophy, etc. The uttermost advantages of multifocal ERG are its innocuity, its applicability to children and the very early sensitivity to changes in retinal function.
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Affiliation(s)
- M Zaninetti
- Clinique universitaire d'ophtalmologie, Genève, Suisse.
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Déruaz A, Matter M, Whatham AR, Goldschmidt M, Duret F, Issenhuth M, Safran AB. Can fixation instability improve text perception during eccentric fixation in patients with central scotomas? Br J Ophthalmol 2004; 88:461-3. [PMID: 15031154 PMCID: PMC1772104 DOI: 10.1136/bjo.2003.025601] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2003] [Indexed: 11/03/2022]
Abstract
BACKGROUND Oculomotor behaviour was investigated in 14 patients with central scotomas from age related macular degeneration (AMD) or Stargardt's disease. A scanning laser ophthalmoscope (SLO) was used to project letters and words onto the retina and to assess fixation behaviour. Five patients reported while deciphering letters that they needed to "move their eye" to prevent the image from vanishing. The observation of the SLO fundus images revealed that the gradual disappearance of the stimulus did not result from a transient projection of the word in the lesion. This prompted the authors to investigate, in an experimental setting, whether purposeful changes in fixation position could improve the perception of an eccentrically fixated text stimulus. METHODS Twenty normal subjects were asked to alternate fixation, every three to four seconds, between two vertically aligned dots, spaced 10 degrees apart, and to report any changes in the perception of a laterally located letter, 1.5 degrees in height, 7 degrees apart and equidistant between the two fixation spots. RESULTS Nineteen subjects reported a transient refreshment of the letter image immediately after the realisation of a saccade. Improved perception lasted approximately a second. With persistent fixation, they noted a rapid fading effect that reduced letter recognition. CONCLUSION These observations suggest that ocular instability during eccentric viewing can have a functional advantage, probably related to counteracting Troxler's phenomenon. In addition to alternating between PRLs, it appears that saccades related to fixation instability might be valuable and improve text perception in individuals with a central scotoma and eccentric fixation. This possibility should be taken into consideration when conducting visual rehabilitation procedures.
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Affiliation(s)
- A Déruaz
- Neuro-ophthalmology Unit, Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, 22 Alcide Jentzer, 1211 Geneva 14, Switzerland.
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Lecchi M, Marguerat A, Ionescu A, Pelizzone M, Renaud P, Sommerhalder J, Safran AB, Tribollet E, Bertrand D. Ganglion cells from chick retina display multiple functional nAChR subtypes. Neuroreport 2004; 15:307-11. [PMID: 15076758 DOI: 10.1097/00001756-200402090-00019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We have examined the properties of nicotinic acetylcholine receptors in embryonic chick retinal ganglion cells. Ganglion cells, identified according to morphological and physiological criteria, displayed spontaneous or induced action potentials. In 94/99 cells acetylcholine pulses evoked responses. In current clamp mode, acetylcholine provoked membrane depolarization and triggered action potentials. Under voltage clamp conditions, acetylcholine evoked inward currents that were readily blocked by d-tubocurarine. Antagonists specific for homomeric (alpha-bungarotoxin) and heteromeric (dihydro-beta-erythroidine) receptors revealed that ganglion cells express multiple functional receptor subtypes. These findings demonstrate that ACh modulates the electrical activity of these cells and is likely to mediate synaptic transmission. The presence of multiple receptor subtypes may contribute to processing and transmission of information in the retina.
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Affiliation(s)
- M Lecchi
- Department of Physiology, Faculty of Medicine, CH-1211, CMU 1, rue M. Servet, Geneva 4, Switzerland
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41
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Affiliation(s)
- Christina Pieh
- Department of Clinical Neurosciences, Geneva University Hospitals, Switzerland.
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Baglivo E, Kapetanios A, Safran AB. Fluorescein and indocyanine green angiographic features in acute syphilitic macular placoid chorioretinitis. Can J Ophthalmol 2003; 38:401-5. [PMID: 12956283 DOI: 10.1016/s0008-4182(03)80053-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Edoardo Baglivo
- Uveitis Unit, Department of Ophthalmology, Hôpitaux Universitaires Genève, rue Alcide-Jentzer, 22, CH-1205, Geneva, Switzerland.
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Abstract
Motion blindness (MB) is defined as the selective disturbance of visual motion perception despite intact perception of other features of the visual scene. MB is characterized by a pandirectional deficit of motion direction discrimination and is assumed to result from damage to the visual motion pathway, especially area MT/V5. However, the most characteristic feature of primate MT/V5 neurons is not their motion selectivity but their preference for one direction of motion (direction selectivity), which changes incrementally at neighbouring columns. In addition to this microscopic directional organization, studies in nonhuman and human primates suggest that single directions of motion are also coded at a more macroscopic level. We thus hypothesized that if MB in humans results from damage to direction-selective neurons in the visual motion pathway, posterior brain damage might cause MB which is direction selective, not pandirectional. The present study investigated motion direction discrimination in patients with posterior unilateral brain damage and determined separate psychophysical thresholds for the four cardinal directions. In addition, we analysed whether the direction of erroneous motion perception (i.e. the perception of right motion for upward motion) was random or showed a directional bias. We report three principal findings. First, motion direction discrimination was severely impaired in one or two directions while it was normal in the other directions. This constituted direction-selective MB. Second, MB was characterized not only by a quantitative direction-selective increase in psychophysical thresholds but also by a qualitative impairment of perceiving motion direction systematically in wrong directions. Both findings suggest that the cortical modules specialized for the perception of a single direction of motion might be larger than previously thought. Third, lesion analysis showed that unilateral damage, not only the human homologue of MT/V5 but also to parieto-occipital cortex, leads to MB.
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Affiliation(s)
- Olaf Blanke
- Department of Neurology, University Hospital of Geneva, 24 rue Micheli-du-Crest, 1211 Geneva, Switzerland.
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Baglivo E, Safran AB. Haemorrhagic toxoplasmic retinochoroiditis: description of an unusual clinical presentation. Br J Ophthalmol 2003; 87:1051-2. [PMID: 12881359 PMCID: PMC1771807 DOI: 10.1136/bjo.87.8.1051-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2003] [Indexed: 11/03/2022]
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Abstract
INTRODUCTION A prominent neurophysiological model of phobia generation holds that specific phobia might result from the uncoupling of unaware subcortical fear responses from aware cortical fear responses. Former responses are thought to be automatic and fast, providing approximate information about the external stimulus, whereas the latter responses are more controlled and allow comparison with previous experience. Since only the cortical pathway carries information available to awareness, this model also accounts for the striking irrationality of specific phobia in humans. METHODS Here, we report neuropsychological and neuro-ophthalmological findings in a 41-year-old patient who developed severe dog phobia following bilateral parietal lobe damage. RESULTS The examinations showed a severe deficit in visual motion perception (visual motion blindness or akinetopsia) as well as spatial vision. Importantly, the patient was largely unaware of his visual deficits. CONCLUSION Based on the present observation it is argued that irrational fear, as found in specific phobia, might not only result from a general uncoupling of aware cortical from unaware subcortical fear responses, but also from a functionally similar dissociation at the cortical level.
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Affiliation(s)
- O Blanke
- Department of Neurology, University Hospital of Geneva, Switzerland.
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Abstract
Conscious experience is an essential part of normal human life and interaction with the environment. Yet the nature of consciousness and conscious perception remains a mystery. Because of its subjective nature, consciousness has been difficult to investigate scientifically, but clues have been gained through studies involving patients with cortical lesions. During the past decade, the development of event-related fMRI has provided insights into aspects of conscious perception in control subjects and patients with cortical lesions by correlating awareness and performance with neural activity during visual tasks. This article reviews how recent research has advanced understanding of conscious perception, its relationship to neural activity and visual performance, and how this relationship can be altered by visual dysfunction. It also presents recent research about how conscious awareness of vision might be represented at a neural level in the central nervous system.
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Affiliation(s)
- Andrew R Whatham
- Neuro-ophthalmology Unit, Ophthalmology Clinic, Department of Clinical Neurosciences and Dermatology, Geneva University Hospitals, Rue Micheli-du-Crest, 1211 Geneva, 14 Switzerland
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Abstract
BACKGROUND Postoperative bacterial endophthalmitis are caused in 80 % of the cases by the patient's own flora. Most of the time, bacterial agents are Gram-positive ((2/3) of cases) and more rarely Gram-negative ((1/3) of cases). Usually, Pseudomonas sp, Proteus sp or Klebsiella sp are isolated, but very rarely Morganella morganii. HISTORY AND SIGNS We describe a case of a Morganella morganii endophthalmitis which occurred after a vitrectomy. THERAPY AND OUTCOME Bacterial examinations disclosed the presence of Morganella morganii in the vitreous. An aggressive treatment (intravitreous [ceftazidim, vancomycin], topical [gentamycin, chloramphenicol] and intravenous [imipenem, ofloxacin] antibiotics) was introduced. In spite of this treatment, the outcome was not favorable. CONCLUSIONS Post-vitrectomy endophthalmitis is very rare and the isolation of a Gram-negative bacteria, in this case Morganella morganii, is infrequent. The outcome of these infections is often poor despite the introduction of a rapid, specific and aggressive treatment.
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Chaloupka K, Baglivo E, Hofer M, Chizzolini C, Delavelle J, Rossillion B, Safran AB. [Cerebral sinus thrombosis in Behçet disease: case report and review of the literature]. Klin Monbl Augenheilkd 2003; 220:186-8. [PMID: 12664376 DOI: 10.1055/s-2003-38186] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Behçet's disease is a chronic inflammatory disorder, clinically characterised by multisystemic vasculitis. Primary neurologic involvement in childhood is quite exceptional. We report a case of a child with recurrent venous thrombosis of the dural sinus. Behçet's disease was diagnosed. HISTORY AND SIGNS A 13-year-old boy from Eritrea was referred to our clinic with severe headaches and photophobia one month after onset. Ophthalmological examination disclosed a bilateral papilledema. Recurrent oral ulcers and pseudo-folliculitis were present. Pathergy test was positive. THERAPY AND OUTCOME Complementary investigations disclosed an inflammatory syndrome. Computertomography was normal. Cranial magnetic resonance venography disclosed multiple cerebral sinus thrombosis (superior sagittal sinus, sigmoid sinus and lateral left sinus). There was no evidence of infectious, inflammatory or hypercoagulation disorder. A Behçet's disease was diagnosed based on the medical history and clinical examination. Whilst his general health deteriorated rapidly before treatment, he improved quickly after the onset of therapy with immunosuppression (Prednisone and Ciclosporine) in combination with anticoagulation (coumarin/Sintrom). CONCLUSION Behçet's disease is uncommon and difficult to diagnose in children. Neurologic involvement as a first presentation is rarely described, but might be underestimated. We emphasise, therefore, the systematic application of magnetic resonance venography in children with unclear persistent headaches.
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Affiliation(s)
- Karla Chaloupka
- Clinique d'Ophtalmologie, Département de neurosciences cliniques, Hôpitaux Universitaires de Genève, Genève, Suisse.
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Baglivo E, Seghelmeble C, Bagnoud M, Leuenberger PM, Safran AB. Indocyanine green angiographic features in endogenous Candida chorioretinis. Klin Monbl Augenheilkd 2003; 220:179-81. [PMID: 12728921 DOI: 10.1055/s-2003-38192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND To describe indocyanine green (ICG) angiography (ICGA) findings and clinical features of endogenous mycotic endophthalmitis. PATIENTS AND METHODS Two patients (a female 62 years, a male 31 years) were addressed to investigate a progressive unilateral visual loss. Slit-lamp examination disclosed a macular chorioretinitis. A clinical work-up revealed a mycotic infection (Candida albicans). Before treatment an ICGA was performed. RESULTS ICGA early frames disclosed hypofluorescent lesions. Progressively, the lesions were surrounded by a slight hyperfluorescence, although the centre of the lesions was still hypofluorescent. CONCLUSIONS The presence and persistence of a hypofluorescent lesion after introducing a specific treatment, led us to suspect a necrotic/ischaemic process affecting the choroidal vascular bed. ICGA provided additional information regarding the pathophysiological process and the patient's functional visual recovery.
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Abstract
BACKGROUND Amyloidosis is an extracellular accumulation of a clear substance called amyloid in different organs. Fragments of identical proteinic chains are the components of this substance. Amyloidosis can be primary, secondary (chronic inflammation, multiple myeloma, tumour), senile or hereditary. HISTORY AND SIGNS A 59-year-old healthy patient was referred with recurrent subconjunctival haemorrhages in his right eye since one year. The clinical examination disclosed the presence of yellowish subconjunctival deposits associated with haemorrhages. THERAPY AND OUTCOME Histopathologic examination of these deposits revealed the presence of amyloid. A complete work-up to exclude a systemic disease gave negative results. CONCLUSIONS Primary conjunctival amyloidosis is a rare clinical entity that is mainly diagnosed histopathologically. In the presence of a recurrent hyposphagma of unknown aetiology the diagnosis of amyloidosis should be excluded.
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Affiliation(s)
- Catherine G Brozou
- Ophthalmology Clinic, Department of Clinical Neurosciences, Geneva University Hospitals, Switzerland.
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