In the frog retina, extracellular recordings of transient ganglion cells have shown that the inhi... more In the frog retina, extracellular recordings of transient ganglion cells have shown that the inhibitory surround of the receptive field of these cells was mediated by gammaaminobutyric acid and acetylcholine (through the nicotinic receptors). Histoautoradiographic and immunocytochemical studies for the two respectively have shown that these neurotransmitters can act through horizontal and amacrine cells. The separation of the ON and OFF channels mediated by glutamate at the bipolar cell level may also be obtained by glycine and/or acetylcholine (through muscarinic receptors). Respective histoautoradiographic and immunocytochemical studies indicate that these neurotransmitters act at the amacrine cell level. These data are consistent with the functional separation of spatial and temporal organization of retinal information, with horizontal cells especially responsible for the spatial organization of the ganglion cell responses and amacrine cells involved in both spatial and temporal organization of the responses. Methods Frogs, Rana esculenta, were used in these experiments. Animal care and
The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 1... more The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 populationbased studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170,000 European participants. The aim of the consortium is to promote and sustain collaboration and sharing of data and knowledge in the field of ophthalmic epidemiology in Europe, with particular focus on the harmonization of methods for future research, estimation and projection of frequency and impact of visual On behalf of the European Eye Epidemiology (E3) consortium. Please see ''Appendix'' section for European Eye Epidemiology (E3) consortium members.
Retinitis pigmentosa (RP) is an inherited retinal degeneration that affects predominantly periphe... more Retinitis pigmentosa (RP) is an inherited retinal degeneration that affects predominantly peripheral visual fields. Macular edema may cause additional central visual acuity decrease. Fluorescein angiography and/or optical coherence tomography detect the presence of macular edema in 10-20% of RP patients. Macular edema can manifest at any stage of the disease and may be unilateral or bilateral. In X-linked forms, macular edema is very rare. The origin of macular edema in RP patients still remains poorly understood. The possible pathophysiological role of autoantibodies has been suggested (retinal, carbonic anhydrase, and enolase antibodies). Drug therapy is the primary treatment for macular edema in patients with R P. Systemic carbonic anhydrase inhibitors, such as oral acetazolamide or topical dorzolamide, still are the mainstay of initial therapy. If cystoid macular edema is refractory to acetazolamide, intravitreal corticosteroid injections could be administered. Intravitreal anti-vascular endothelial growth factor therapy has also been used in cases of macular edema persistence after oral acetazolamide therapy, though with uncertain results. Vitrectomy can also be proposed, but its role is not clear yet. Autoimmune retinopathies (AIRs) are a group of rare diseases characterized by acute or subacute progressive vision loss and are thought to be mediated by autoantibodies specific to retinal antigens. The AIRs encompass paraneoplastic syndromes, such as cancer-associated retinopathy and melanoma-associated retinopathy, and a larger group of AIRs that have similar clinical and immunological findings but without underlying malignancy. These diseases may also be complicated by macular edema.
The anticonvulsant drug lamotrigine has been shown to produce antidepressant effects in patients ... more The anticonvulsant drug lamotrigine has been shown to produce antidepressant effects in patients with bipolar disorder. To date, only a few preclinical studies have been conducted using lamotrigine treatment in the forced swim test (FST), an animal model of depression with low face validity. The underlying mechanisms by which lamotrigine works have not been well characterized either. This study extends earlier work on the role of brain-derived neurotrophic factor (BDNF) in regulating the antidepressant actions of lamotrigine. We showed that in rats subjected to chronic unpredictable stress, chronic administration of 30 mg/kg lamotrigine ameliorates behavioural deficits of stressed rats in both sucrose preference test (SPT) and novelty-suppressed feeding test (NSFT). In parallel, chronic lamotrigine treatment up-regulates frontal and hippocampal BDNF protein expression in both naive and stressed animals, and restores the stress-induced down-regulation of BDNF levels. In addition, inhibition of BDNF signalling by infusion of K252a, an inhibitor of the BDNF receptor TrkB, blocks the antidepressant effects of lamotrigine in SPT, NSFT and FST. Taken together, this study provides further evidence that BDNF is an essential mediator for the antidepressant effects of lamotrigine.
Increasingly in our clinical practice, we have to deal with the common occurrence of ocular dryne... more Increasingly in our clinical practice, we have to deal with the common occurrence of ocular dryness. In 1982, the French Society of Ophthalmology elected to devote its 1987 annual report to this problem. This book represents the results of five years of collaborative work aimed at updating our clinical, physiologic, immunologic, histopathologic, and even socioeconomic knowledge of this group of diseases. The authors attempt to bring the data from basic science to clinical application. Most often, emphasis is placed on the lack of definitive answers to essential clinical interrogations, such as the exact borders of ocular dryness, the value of lacrimal secretion tests, and the effectiveness of the treatments available today. Clearly, despite an unexpected ordering of the chapters (the anatomic and physiologic data are given only after the pathologic aspects), this "... this study is comprehensive and represents a valuable source of state-of-the-art information for clinicians as well as scientists."
Laser Doppler holography (LDH) is a full-field blood flow imaging technique able to reveal human ... more Laser Doppler holography (LDH) is a full-field blood flow imaging technique able to reveal human retinal and choroidal blood flow with high temporal resolution. We here report on using LDH in the anterior segment of the eye without making changes to the instrument. Blood flow in the bulbar conjunctiva and episclera as well as in corneal neovascularization can be effectively imaged. We additionally demonstrate simultaneous holographic imaging of the anterior and posterior segments by simply adapting the numerical propagation distance to the plane of interest. We used this feature to track the movements of the retina and pupil with high temporal resolution. Finally, we show that the light backscattered by the retina can be used for retro-illumination of the anterior segment. Hence digital holography can reveal opacities caused by absorption or diffusion in the cornea and eye lens.
The eye offers a unique opportunity for non-invasive exploration of cardiovascular diseases. Opti... more The eye offers a unique opportunity for non-invasive exploration of cardiovascular diseases. Optical angiography in the retina requires sensitive measurements, which hinders conventional full-field laser Doppler imaging schemes. To overcome this limitation, we used digital holography to perform laser Doppler perfusion imaging of human retina with near-infrared light. Two imaging channels with a slow and a fast CMOS camera were used simultaneously for real-time narrowband measurements, and offline wideband measurements, respectively. The beat frequency spectrum of optical interferograms recorded with the fast (up to 75 kHz) CMOS camera was analyzed by short-time Fourier transformation. Power Doppler images drawn from the Doppler power spectrum density qualitatively revealed blood flow in retinal vessels over 512 × 512 pixels covering 2.4 × 2.4 mm 2 on the retina with a temporal resolution down to 1.6 ms. The sensitivity to lateral motion as well as the requirements in terms of sampling frequency are discussed.
To analyze the efficacy of aflibercept switch treatment for regression of pigment epithelial deta... more To analyze the efficacy of aflibercept switch treatment for regression of pigment epithelial detachment (PED) in patients previously treated with ranibizumab. Multicenter, prospective, nonrandomized clinical trial. One eye of patients presenting neovascular age-related macular degeneration with PED of more than 250 μm in height, with persistent fluid, was included. Patients had to have received at least six ranibizumab intravitreal injections during the 12 months before enrollment. Patients were switched from ranibizumab pro re nata to aflibercept (fixed regimen, 3 monthly intravitreal injections, and then Q6). Main outcome measure was change in PED height from baseline to Week 12 after switch. Secondary outcomes were best-corrected visual acuity and PED volume changes. Eighty four patients were included. Mean delay between last ranibizumab intravitreal injection and switch was 44.7 days. Mean maximal PED height at baseline visit was 347 μm (±109) and reduced to a mean of 266 μm (±1...
Investigative ophthalmology & visual science, Feb 1, 2017
Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may caus... more Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may cause retinal edema often responsible for vision loss. Dexamethasone is used in clinical practice to restore iBRB. The aim of this study was to characterize the impact of a surgically induced iBRB breakdown on retinal homeostatic changes due to dystrophin Dp71, aquaporin-4 (AQP4), and Kir4.1 alterations in Müller glial cells (MGC) in a mouse model. The protective effect of dexamethasone was assessed in this model. Moreover, retinal explants were used to control MGC exposure to a hypoosmotic solution containing barium. Partial lens surgery was performed in C57BL6/J mice. Dystrophin Dp71, AQP4, and Kir4.1 expression was analyzed by quantitative RT-PCR, Western blot, and immunohistochemistry. Twenty-four hours after surgery, mice received a single intravitreal injection of dexamethasone or of vehicle. After partial lens surgery, iBRB permeability increased while Dp71 and AQP4 were downregulated...
Purpose: Retinitis pigmentosa (RP) is a group of inherited retinal degenerations leading to blind... more 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. Ophthalmology 2015;-:1e8
Investigative ophthalmology & visual science, Jan 20, 2014
With a retinal prosthesis connected to a head-mounted camera (camera-connected prosthesis [CC-P])... more 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. 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. Misaligned head and gaze directions oc...
Purpose. This study aimed at assessing the prevalence of pathologies presenting retinal inner nuc... more Purpose. This study aimed at assessing the prevalence of pathologies presenting retinal inner nuclear layer (RINL) microcystic perimacular changes associated with optic nerve atrophy (OA). The charts of patients presenting a significant defect of the Retinal Nerve Fiber Layer (RNFL) were included prospectively in this study. Patients were classified according to the etiology of the RNFL defect. Two hundred and one eyes of 138 patients were enrolled in this analysis. Retinal images obtained showed the typical hyporeflective perifoveal crescent-shaped lesion composed of small round hyporeflective microcysts confined to the RINL in 35.3% of the eyes. Those findings were found in 75% of eyes presenting hereditary OA, 50% of eyes presenting ischemic optic neuritis, 50% of eyes with drusen of the optic nerve (ON), 44.4% of eyes presenting a compressive OA, 32% of eyes presenting inflammatory optic neuropathy from multiple sclerosis, 18.5% of eyes presenting OA from undetermined origin, an...
Reçu le 24 janvier 2013 Résumé-Les prothèses rétiniennes visentà restaurer une fonction visuelle ... more Reçu le 24 janvier 2013 Résumé-Les prothèses rétiniennes visentà restaurer une fonction visuelle utile chez des patients devenus aveugles par suite de la perte de leurs photorécepteurs. Les essais cliniques récents ont démontré la faisabilité de cette approche. Malgré un nombre limité d'électrodes (60) et donc a fortiori de pixels, certains patients sont en effet capables de lire des mots ou de reconnaître des objets très contrastés. Ces résultats soulèvent de nouveaux défis pour augmenter le nombre et la densité desélectrodes afin d'améliorer l'acuité visuelle des patients pour autoriser des tâches complexes comme la locomotion autonome ou la reconnaissance des visages. Cette revue présente les résultats des essais cliniques sur les dispositifs les plus avancés puis les défis et solutions envisagées.
In the frog retina, extracellular recordings of transient ganglion cells have shown that the inhi... more In the frog retina, extracellular recordings of transient ganglion cells have shown that the inhibitory surround of the receptive field of these cells was mediated by gammaaminobutyric acid and acetylcholine (through the nicotinic receptors). Histoautoradiographic and immunocytochemical studies for the two respectively have shown that these neurotransmitters can act through horizontal and amacrine cells. The separation of the ON and OFF channels mediated by glutamate at the bipolar cell level may also be obtained by glycine and/or acetylcholine (through muscarinic receptors). Respective histoautoradiographic and immunocytochemical studies indicate that these neurotransmitters act at the amacrine cell level. These data are consistent with the functional separation of spatial and temporal organization of retinal information, with horizontal cells especially responsible for the spatial organization of the ganglion cell responses and amacrine cells involved in both spatial and temporal organization of the responses. Methods Frogs, Rana esculenta, were used in these experiments. Animal care and
The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 1... more The European Eye Epidemiology (E3) consortium is a recently formed consortium of 29 groups from 12 European countries. It already comprises 21 populationbased studies and 20 other studies (case-control, cases only, randomized trials), providing ophthalmological data on approximately 170,000 European participants. The aim of the consortium is to promote and sustain collaboration and sharing of data and knowledge in the field of ophthalmic epidemiology in Europe, with particular focus on the harmonization of methods for future research, estimation and projection of frequency and impact of visual On behalf of the European Eye Epidemiology (E3) consortium. Please see ''Appendix'' section for European Eye Epidemiology (E3) consortium members.
Retinitis pigmentosa (RP) is an inherited retinal degeneration that affects predominantly periphe... more Retinitis pigmentosa (RP) is an inherited retinal degeneration that affects predominantly peripheral visual fields. Macular edema may cause additional central visual acuity decrease. Fluorescein angiography and/or optical coherence tomography detect the presence of macular edema in 10-20% of RP patients. Macular edema can manifest at any stage of the disease and may be unilateral or bilateral. In X-linked forms, macular edema is very rare. The origin of macular edema in RP patients still remains poorly understood. The possible pathophysiological role of autoantibodies has been suggested (retinal, carbonic anhydrase, and enolase antibodies). Drug therapy is the primary treatment for macular edema in patients with R P. Systemic carbonic anhydrase inhibitors, such as oral acetazolamide or topical dorzolamide, still are the mainstay of initial therapy. If cystoid macular edema is refractory to acetazolamide, intravitreal corticosteroid injections could be administered. Intravitreal anti-vascular endothelial growth factor therapy has also been used in cases of macular edema persistence after oral acetazolamide therapy, though with uncertain results. Vitrectomy can also be proposed, but its role is not clear yet. Autoimmune retinopathies (AIRs) are a group of rare diseases characterized by acute or subacute progressive vision loss and are thought to be mediated by autoantibodies specific to retinal antigens. The AIRs encompass paraneoplastic syndromes, such as cancer-associated retinopathy and melanoma-associated retinopathy, and a larger group of AIRs that have similar clinical and immunological findings but without underlying malignancy. These diseases may also be complicated by macular edema.
The anticonvulsant drug lamotrigine has been shown to produce antidepressant effects in patients ... more The anticonvulsant drug lamotrigine has been shown to produce antidepressant effects in patients with bipolar disorder. To date, only a few preclinical studies have been conducted using lamotrigine treatment in the forced swim test (FST), an animal model of depression with low face validity. The underlying mechanisms by which lamotrigine works have not been well characterized either. This study extends earlier work on the role of brain-derived neurotrophic factor (BDNF) in regulating the antidepressant actions of lamotrigine. We showed that in rats subjected to chronic unpredictable stress, chronic administration of 30 mg/kg lamotrigine ameliorates behavioural deficits of stressed rats in both sucrose preference test (SPT) and novelty-suppressed feeding test (NSFT). In parallel, chronic lamotrigine treatment up-regulates frontal and hippocampal BDNF protein expression in both naive and stressed animals, and restores the stress-induced down-regulation of BDNF levels. In addition, inhibition of BDNF signalling by infusion of K252a, an inhibitor of the BDNF receptor TrkB, blocks the antidepressant effects of lamotrigine in SPT, NSFT and FST. Taken together, this study provides further evidence that BDNF is an essential mediator for the antidepressant effects of lamotrigine.
Increasingly in our clinical practice, we have to deal with the common occurrence of ocular dryne... more Increasingly in our clinical practice, we have to deal with the common occurrence of ocular dryness. In 1982, the French Society of Ophthalmology elected to devote its 1987 annual report to this problem. This book represents the results of five years of collaborative work aimed at updating our clinical, physiologic, immunologic, histopathologic, and even socioeconomic knowledge of this group of diseases. The authors attempt to bring the data from basic science to clinical application. Most often, emphasis is placed on the lack of definitive answers to essential clinical interrogations, such as the exact borders of ocular dryness, the value of lacrimal secretion tests, and the effectiveness of the treatments available today. Clearly, despite an unexpected ordering of the chapters (the anatomic and physiologic data are given only after the pathologic aspects), this "... this study is comprehensive and represents a valuable source of state-of-the-art information for clinicians as well as scientists."
Laser Doppler holography (LDH) is a full-field blood flow imaging technique able to reveal human ... more Laser Doppler holography (LDH) is a full-field blood flow imaging technique able to reveal human retinal and choroidal blood flow with high temporal resolution. We here report on using LDH in the anterior segment of the eye without making changes to the instrument. Blood flow in the bulbar conjunctiva and episclera as well as in corneal neovascularization can be effectively imaged. We additionally demonstrate simultaneous holographic imaging of the anterior and posterior segments by simply adapting the numerical propagation distance to the plane of interest. We used this feature to track the movements of the retina and pupil with high temporal resolution. Finally, we show that the light backscattered by the retina can be used for retro-illumination of the anterior segment. Hence digital holography can reveal opacities caused by absorption or diffusion in the cornea and eye lens.
The eye offers a unique opportunity for non-invasive exploration of cardiovascular diseases. Opti... more The eye offers a unique opportunity for non-invasive exploration of cardiovascular diseases. Optical angiography in the retina requires sensitive measurements, which hinders conventional full-field laser Doppler imaging schemes. To overcome this limitation, we used digital holography to perform laser Doppler perfusion imaging of human retina with near-infrared light. Two imaging channels with a slow and a fast CMOS camera were used simultaneously for real-time narrowband measurements, and offline wideband measurements, respectively. The beat frequency spectrum of optical interferograms recorded with the fast (up to 75 kHz) CMOS camera was analyzed by short-time Fourier transformation. Power Doppler images drawn from the Doppler power spectrum density qualitatively revealed blood flow in retinal vessels over 512 × 512 pixels covering 2.4 × 2.4 mm 2 on the retina with a temporal resolution down to 1.6 ms. The sensitivity to lateral motion as well as the requirements in terms of sampling frequency are discussed.
To analyze the efficacy of aflibercept switch treatment for regression of pigment epithelial deta... more To analyze the efficacy of aflibercept switch treatment for regression of pigment epithelial detachment (PED) in patients previously treated with ranibizumab. Multicenter, prospective, nonrandomized clinical trial. One eye of patients presenting neovascular age-related macular degeneration with PED of more than 250 μm in height, with persistent fluid, was included. Patients had to have received at least six ranibizumab intravitreal injections during the 12 months before enrollment. Patients were switched from ranibizumab pro re nata to aflibercept (fixed regimen, 3 monthly intravitreal injections, and then Q6). Main outcome measure was change in PED height from baseline to Week 12 after switch. Secondary outcomes were best-corrected visual acuity and PED volume changes. Eighty four patients were included. Mean delay between last ranibizumab intravitreal injection and switch was 44.7 days. Mean maximal PED height at baseline visit was 347 μm (±109) and reduced to a mean of 266 μm (±1...
Investigative ophthalmology & visual science, Feb 1, 2017
Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may caus... more Breakdown of the inner blood-retinal barrier (iBRB) occurs in many retinal disorders and may cause retinal edema often responsible for vision loss. Dexamethasone is used in clinical practice to restore iBRB. The aim of this study was to characterize the impact of a surgically induced iBRB breakdown on retinal homeostatic changes due to dystrophin Dp71, aquaporin-4 (AQP4), and Kir4.1 alterations in Müller glial cells (MGC) in a mouse model. The protective effect of dexamethasone was assessed in this model. Moreover, retinal explants were used to control MGC exposure to a hypoosmotic solution containing barium. Partial lens surgery was performed in C57BL6/J mice. Dystrophin Dp71, AQP4, and Kir4.1 expression was analyzed by quantitative RT-PCR, Western blot, and immunohistochemistry. Twenty-four hours after surgery, mice received a single intravitreal injection of dexamethasone or of vehicle. After partial lens surgery, iBRB permeability increased while Dp71 and AQP4 were downregulated...
Purpose: Retinitis pigmentosa (RP) is a group of inherited retinal degenerations leading to blind... more 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. Ophthalmology 2015;-:1e8
Investigative ophthalmology & visual science, Jan 20, 2014
With a retinal prosthesis connected to a head-mounted camera (camera-connected prosthesis [CC-P])... more 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. 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. Misaligned head and gaze directions oc...
Purpose. This study aimed at assessing the prevalence of pathologies presenting retinal inner nuc... more Purpose. This study aimed at assessing the prevalence of pathologies presenting retinal inner nuclear layer (RINL) microcystic perimacular changes associated with optic nerve atrophy (OA). The charts of patients presenting a significant defect of the Retinal Nerve Fiber Layer (RNFL) were included prospectively in this study. Patients were classified according to the etiology of the RNFL defect. Two hundred and one eyes of 138 patients were enrolled in this analysis. Retinal images obtained showed the typical hyporeflective perifoveal crescent-shaped lesion composed of small round hyporeflective microcysts confined to the RINL in 35.3% of the eyes. Those findings were found in 75% of eyes presenting hereditary OA, 50% of eyes presenting ischemic optic neuritis, 50% of eyes with drusen of the optic nerve (ON), 44.4% of eyes presenting a compressive OA, 32% of eyes presenting inflammatory optic neuropathy from multiple sclerosis, 18.5% of eyes presenting OA from undetermined origin, an...
Reçu le 24 janvier 2013 Résumé-Les prothèses rétiniennes visentà restaurer une fonction visuelle ... more Reçu le 24 janvier 2013 Résumé-Les prothèses rétiniennes visentà restaurer une fonction visuelle utile chez des patients devenus aveugles par suite de la perte de leurs photorécepteurs. Les essais cliniques récents ont démontré la faisabilité de cette approche. Malgré un nombre limité d'électrodes (60) et donc a fortiori de pixels, certains patients sont en effet capables de lire des mots ou de reconnaître des objets très contrastés. Ces résultats soulèvent de nouveaux défis pour augmenter le nombre et la densité desélectrodes afin d'améliorer l'acuité visuelle des patients pour autoriser des tâches complexes comme la locomotion autonome ou la reconnaissance des visages. Cette revue présente les résultats des essais cliniques sur les dispositifs les plus avancés puis les défis et solutions envisagées.
Uploads
Papers by José A Sahel