Actualité internationale
2007 
2007 
| LE MONDE | 08.09.07
Lire au tableau devient facile pour des enfants malvoyants grâce à la technologie numérique. A l'école spécialisée du Château, à Nice, neuf élèves handicapés par une vision inférieure à 3/10e après correction sont équipés, pour la deuxième année consécutive, d'un ordinateur portable doté d'un logiciel d'aide à la vision, spécialement conçu pour la lecture de documents éloignés. Concrètement, l'ordinateur est relié à une caméra de bonne qualité, qui filme le tableau sur lequel écrit l'enseignant. |
Le logiciel Portanum zoome le texte et lui applique des traitements d'image pour l'adapter à la vision des enfants (fausses couleurs, amélioration du contraste, de la luminosité...). Cette innovation a été concrétisée à l'initiative de l'Association des parents d'enfants déficients visuels (Apedv) des Alpes-Maritimes avec le concours de Thales et d'IBM, qui ont fourni gratuitement les logiciels et les ordinateurs. "Grâce à cette technologie, l'intégration de nos élèves malvoyants au collège puis au lycée va être facilitée", prévoit le directeur de l'école, Lionel Edouard. L'Apedv tente de monter à Nice une filière Portanum du collège à l'université. Le logiciel est téléchargeable gratuitement sur http://www.portanum.com/ |
| LE MONDE | 10.09.07
Surfer sur Internet, cliquer sur une souris, envoyer un mail... Des procédures simples, devenues presque des gestes de tous les jours pour tout un chacun. Mais qui s'avèrent nettement plus complexes pour les personnes déficientes visuelles. C'est pourquoi François Condello, mécanicien de 58 ans à la retraite et lui-même malvoyant, a créé winaide.net. Un site d'entraide et de dépannage qui permet aux personnes aveugles ou malvoyantes de se former à l'utilisation et à la manipulation du matériel informatique. "Comment font-ils pour lire et taper sur le clavier?" Une interrogation qui revient souvent à la bouche du néophyte lorsqu'il imagine un aveugle devant un écran d'ordinateur. Il existe de nombreux outils mis au point pour leur permettre d'accéder aux technologies de communication. Du terminal braille qui transcrit les données apparaissant à l'écran au lecteur de synthèse vocale qui déchiffre à haute voix, un éventail de logiciels de plus en plus perfectionnés est proposé aux déficients visuels. Encore faut-il qu'ils aient connaissance de ces outils et qu'ils sachent s'en servir. "L'informatique est une chance pour l'autonomie et l'intégration des aveugles. Il ne faudrait pas que la complexité des nouvelles interfaces graphiques laisse sur le bord du chemin ceux qui n'ont pas les moyens d'accéder aux formations à ces outils", explique François Condello. |
UNE AIDE SANS ÉQUIVALENT Sur winaide.net, une liste de discussion qui réunit plus de 600 adhérents (tous malvoyants ou aveugles) permet à chacun d'apporter son aide ou de faire part de ses interrogations sur un sujet. Ces informations échangées sont ensuite vérifiées, complétées et mises en forme sur le site dans des articles classés par thèmes et accessibles gratuitement. Dépassées les difficultés techniques, reste encore un problème de taille. Tout comme la majorité des lieux publics restent inadaptés aux handicapés, Internet est encore un espace où l'on se soucie peu des minorités. En effet, malgré les recommandations du World Wide Web Consortium (W3C), organisme indépendant qui vise à garantir un accès équitable à tout contenu Web, force est de constater que de nombreux sites sont encore incompatibles avec les outils utilisés par les aveugles. "75% des sites nous restent interdits parce qu'ils sont trop évolués et que les images n'ont pas leur équivalent textuel. Les handicapés ne rentrent pas dans les préoccupations des concepteurs", déplore François Condello. L'accès à Internet des déficients visuels est pourtant un enjeu essentiel. Car une fois dépassés les premiers obstacles, Internet est pour eux une aide sans équivalent et qui leur facilite grandement la vie de tous les jours. Géraldine Bordère |
| Stem cell therapy for eye disease (http://news.bbc.co.uk/2/hi/health/6721685.stm):
UK scientists are attempting to restore vision in people with a leading cause of blindness using stem cells. The team has already repaired the vision of a handful of patients with age-related macular degeneration using cells from the patients' own eyes. With the help of a £4m donation, they are now planning to carry out the same operation using retinal cells grown from stem cells in the lab. It is hoped the first patients would be treated within five years. Age-related macular degeneration (AMD) affects around 25% of over-60s in the UK to some degree and causes blindness in 14 million people across Europe. There are two types - dry - which makes up 90% of cases, and wet, which makes up the other 10%. It is caused by the failure of retinal pigment epithelial cells (RPE) - a layer of support cells under the retina, which processes light. This leads to the degeneration of the macula - the central area of the retina - and gradually knocks out central vision. Using stem cells - which are far more adaptable - can only improve success of what has already been achieved and in addition establish this as a global therapy Professor Pete Coffey There are treatments for wet AMD but not for dry AMD. Mr Lyndon Da Cruz, consultant ophthalmic surgeon at Moorfields Eye Hospital in London has carried out an operation in a handful of patients to take cells from the healthy periphery of the eye in patients with wet AMD and transplant them into the affected area. The procedures have been successful but are associated with complications, take more than two hours and require two operations. |
To make the procedure quicker, easier and more widely
available, researchers at the University of Sheffield have grown RPE cells
from embryonic stem cell lines.
The hope is that this can be processed into a layer that can be injected into the patient's eye during a simple 45-minute operation. Tests of the laboratory grown RPE cells in rats with AMD showed they restored vision. Collaboration A £4m donation from a US benefactor who wishes to be remain anonymous has enabled the teams to set up the London Project to Cure AMD with the UCL Institute of Ophthalmology. Professor Pete Coffey, director of the Project explained although they had successfully grown RPE cells in the laboratory, they now needed to make sure the cells were safe enough to be used in humans, which would take time. "Using stem cells - which are far more adaptable - can only improve success of what has already been achieved and in addition establish this as a global therapy." "The goal is within five years to have a cohort of patients to put the cells into," added Professor Coffey whose team is preparing the laboratory-derived cells for transplant Mr Cruz added that if in 10 years the four by six mm transplant was not in global use something major would have failed in the research. "We have the RPE, we have the evidence that doing this type of thing can restore vision. It's practicality issues rather than a big unknown." More operations are also planned with the patients' own cells in those suffering from dry AMD to test the procedures effectiveness. Professor Alistair Fielder, senior medical adviser for the eye research charity Fight for Sight, said: "The London Project represents a real chance to tackle this untreatable condition and bring hope to many." |
| WASHINGTON: Electrodes inserted into the brain may point
the way to restoring sight lost to eye disease or trauma.
The research in monkeys is in very early stages but has shown some promise, Harvard Medical School researchers report in Tuesday's issue of Proceedings of the National Academy of Sciences. While researchers have worked on developing implants for the eye's retina, John S. Pezaris and R. Clay Reid turned their attention to a portion of the thalamus that relays signals from the retina to the brain's visual cortex. They were able to get the brains of the monkeys to register a point of light by sending a signal down the electrodes — even though no light was visible, Pezaris said in a telephone interview. "We don't know what it looked like because we can't really ask them," he said. "But there definitely was something." A single point of light may not sound like much, but Pezaris says the next step is to try to get eight points to register, which would allow the researchers to begin forming shapes such as vertical or horizontal lines. "If that works we will try more and more and more," he said. "At some point we hope to move into humans, and once we can do that, even on an experimental basis, the amount we will be able to learn will grow." That is a few years away, he said, but if all goes well it might lead to treatments for people who have lost their vision to accidents, cancer or diseases such as glaucoma and macular degeneration. |
This technique had not been tried because of the
hard-to-reach location of the thalamus, but Pezaris said the advent of
deep brain stimulation for treating Parkinson's disease suggested that
technique might be adapted.
So the researchers placed electrodes in the lateral geniculate nucleus, a section of the thalamus, in test monkeys that had been trained to look at a spot of light on a screen in a darkened room. When the light was placed in different spots, the monkeys looked at it. Pezaris and Reid then stimulated LGN in an area that would have responded to a light in a specific spot, and the monkeys looked at that spot as though a light was there. Dr. Sherry L. Ball, a research health scientist at the Cleveland VA Medical Center, called the work a "very exciting and new approach." "We've always thought that the LGN wasn't a practical site for stimulation with a prosthetic, but this team is starting to prove otherwise. We know the LGN is well organized. This solves the problem of not knowing how to stimulate it and thus makes it a better candidate than the cortex," said Ball, who was not part of the research team. However, Ball added, "The difficulty is going to be in hitting the exact targets in the LGN. Technology is improving all the time, but imaging the LGN for electrode implantation is not yet precise." Pezaris' research was financed by the National Institutes of Health, the Dana/Mahoney Foundation, the Lefler Fund, the Kirsch Foundation and the Bushrod H. Campbell and Adah F. Hall Charity Fund. |
| A bionic implant that
bypasses the eye might eventually treat many forms of blindness.
By Duncan Graham-Rowe  One day it may be possible to restore sight in people who are congenitally blind by placing an implant in a part of the vision system hitherto ignored. Unlike most visual prostheses in advanced development,this new approach could make it possible to treat blindness even when the entire eye is damaged. While the work is still in the early stages, researchers ultimately envision a device that translates images from a digital camera into neural impulses and then feeds that information into the visual system, allowing the wearer to see. Previous research has shown that visual sensations, known as percepts, can be elicited in blind subjects by electrically stimulating nerve cells within the vision system. Researchers at Harvard Medical School, in Boston, are designing a visual prosthesis that builds on that observation. Several types of sight-boosting prostheses are currently under development, with some already being tested in humans. But while these largely target the retina, the Harvard researchers chose to focus on part of the visual system called the lateral geniculate nucleus (LGN), a relay station along the route from the optic nerve to the visual cortex, where visual information is processed. Because it's upstream of the eye, this area could be targeted in people with extensive eye damage. |
And unlike locations in the visual cortex,
the LGN is one of the first "stops" in the visual system, meaning that
the neural signals encoding visual information have not yet been extensively
processed and spread throughout the brain. "[In the LGN] there is a
straightforward mapping of the visual scene on the tissue," says John
Pezaris, a neural-systems engineer at Harvard Medical School, who led
the research. This means that specific parts of the LGN are linked to specific
parts of the visual scene. When a light flashes in one location, for example,
the corresponding area in the LGN will become active.
To determine if activity in the LGN can mimic visual stimuli, the researchers implanted electrodes in the LGNs of two monkeys that had been trained to move their eyes rapidly toward points of light when they appeared on a screen. When a part of the LGN corresponding to a specific part of the visual field was electrically stimulated, the monkeys would shift their gaze to that point on the screen. The results, published today in the Proceedings of the National Academy of Sciences, suggest that the monkeys were "seeing" the pulses in their field of view even though nothing was appearing on the screen. "It's an absolutely stunning piece of work," says James Morrison, a physiologist and principal investigator for the Retinal Prosthesis Group at the University of Glasgow's Institute of Biomedical and Life Sciences, in Scotland. However, Morrison says, the position of the LGN is a major disadvantage of the approach. It's located in the middle of the head, making it difficult to access. Recent advances in neurosurgical techniques, such as deep brain stimulators for treating Parkinson's disease, may help solve this issue: the LGN is just a few centimeters away from where these stimulators are placed, says Pezaris. Still, it's too soon to say whether the findings will lead to better brain implants. "While I think the paper holds scientific merit, I think it will be extremely difficult to restore blindness from there," says Thomas Serre, a neuroscientist at the Center for Biological and Computational Learning at MIT's McGovern Institute for Brain Research. He believes that neurons in the LGN may be spaced too closely together to be stimulated individually, which would be important in trying to reproduce natural vision. "I don't think we will ever be able to go beyond generating very simple percepts like points of light," he says. Pezaris accepts that a tremendous amount of work is needed before the LGN can be used to treat blindness, but he says this work does at least open the door to that possibility. "This was just the first very small step," he says. |