Автор работы: Пользователь скрыл имя, 15 Апреля 2012 в 12:05, реферат
Цель работы: Отыскать проекты, занимающиеся восстановлением зрения слепых людей, при помощи технологий искусственного зрения, а также ознакомиться с текущим прогрессом этих проектов.
Изучить принцип работы зрительного анализатора человека.
Ознакомиться с различными заболеваниями зрительного анализатора, и причинами их возникновений.
Поиск проектов занимающихся разработкой искусственного зрения.
Изучение текущего прогресса этих проектов, ознакомление со статистическими данными и планами исследований.
2.1.1 Прототип «bionic eye»
В апреле 2010 года группа австралийских ученых Bionic Vision Australia представила прототип технологии (Рис. 13), способной вернуть человеку потерянное зрение, будь потеря врожденной, связанной с возрастом или глазными заболеваниями. Увы, о полном восстановлении зрения говорить пока рано. Действующий образец дает возможность лишь ориентироваться в пространстве и избегать препятствий.
Рисунок 13. Прототип bionic eye от австралийских ученых.
По задумке разработчиков, изображение с миниатюрной камеры, встроенной в специальные очки, передается на внешний процессор, находящийся в кармане пользователя, а затем конвертируется в соответствующий формат. Далее по каналу беспроводной связи данные передаются на микрочип, имплантированный в глаз пациента. При помощи электродов чип симулирует работу сетчатки и электрические импульсы поступают по оптическому нерву непосредственно в мозг.
В представленном образце чипа использовалось около 100 электродов, однако уже сейчас ведется работа над чипом второго поколения с увеличенным в 10 раз разрешением, которого, как утверждается, будет достаточно для распознавания лиц и чтения крупных надписей.
Проект финансируется австралий
Далее будет представлена информация с официального сайта проекта Bionic Vision Australia, включая отчет о работе 2010 года. Для наименьшего искажения информации первоисточника, она будет представлена на английском языке.
2.1.2 О Bionic Vision Australia (BVA)
Bionic Vision Australia (BVA) is a national consortium of researchers working together to develop a bionic eye that can restore the sense of vision to people with vision impairment due to retinal degenerative conditions such as retinitis pigmentosa and age-related macular degeneration.
The Australian bionic eye project brings together a cross-disciplinary group of world-leading experts in the fields of ophthalmology, biomedical engineering, electrical engineering and materials science, neuroscience, vision science, psychophysics, wireless integrated-circuit design, and surgical, preclinical and clinical practice.
In December 2009, the Australian Federal Government awarded a $42 million ARC grant to Bionic Vision Australia to develop bionic vision technology.[5]
2.1.3 План исследований BVA
Bionic Vision Australia's goal is to develop a functional retinal prosthesis, otherwise known as a 'bionic eye', that is able to restore the sense of vision to people with inherited and degenerative retinal diseases.
There are two generations of devices in development:
- Wide-view neurostimulator device
- High-acuity neurostimulator device
In addition to developing the hardware for both of these devices, our researchers are working on:
We anticipate that by 2013, the first patient tests of the wide-view neurostimulator device would have been completed. Should these trials be successful, commercialisation of the technology would then follow in 2014.
The high-acuity neurostimulator device is being developed in parallel with the wide-view device and commercialisation will take place in due course.
2.1.4 Wide-view device
Bionic Vision Australia's first prototype retinal prosthesis, the wide-view neurostimulator device (Рис. 14), will utilise an implanted chip with 98 electrodes to stimulate the retina and enable patients to contrast light from dark.
Рисунок 14. Wide-view neurostimulator device.
This device is aimed at providing patients with the ability to manoeuvre around large objects such as buildings, cars and park benches and will be able to lead more independent lives.
The wide-view neurostimulator device may be most suitable for patients with retinitis pigmentosa. We anticipate that the device will be ready for the first tests with patients by 2013.
The Wide-View Device Development team is working on designing the first prototype retinal implant for profoundly blind patients with particular forms of retinal disease. This program is led by the University of New South Wales.
The wide-view electrode array underwent a series of rigorous tests on longevity and charge injection in 2010, resulting in increased confidence that sufficient and safe electrical stimulation will be achieved. In collaboration with the Surgical and Preclinical Programs, the physical strength of electrode array has been enhanced to improve surgical insertion.
Prototypes of the electronic components to be implanted within the eye have been constructed and are in the process of being assessed for implantation suitability by the Surgical Program.
Design of the 98 channel microchip that will form the heart of the wide-view device is complete and manufacture is under way. Methods for hermetic encapsulation (leak-proof seals) have progressed to a mature level of development such that a number of opportunities exist for further miniaturisation and increased complexity. Device longevity testing has shown that the wide-view device is able to pass the same stringent testing applied to Cochlear implants.
The basic framework for the image capture and processing system (camera and computer circuitry) has been completed and will be used to prepare for tests with the first patients.
Building works have commenced in the new implantable bionics laboratories at the University of New South Wales that will include a clean room for implant fabrication, with estimated completion in April 2011.
A/Prof Gregg Suaning (UNSW)
Program Leader, Wide-View Device Development
“We have been working on designing bionic eye prototypes for 14 years. I’m thrilled that we now have such a strong, multidisciplinary team together to help make this idea a reality. The progress to date is remarkable.”
2.1.5 High-Acuity device
Bionic Vision Australia's second prototype retinal prosthesis, the high-acuity neurostimulator device (Рис. 15), builds on the development of the first prototype. The high-acuity device will include an implanted chip with over one thousand electrodes to stimulate the retina and enable patients to perceive more detailed visual information
.
Рисунок 15. High-acuity neurostimulator device.
Patients with the high-acuity device may be able to recognise faces and read large print somewhere between the second and third line of a Snellen chart.
The high-acuity device may be most suitable to patients with age-related macular degeneration and should be ready for the first tests with patients in 2014.
The High-Acuity Device Development team is developing the second prototype retinal implant for patients with particular forms of retinal disease. Predominantly, this program brings together researchers from NICTA and the University of Melbourne.
The first generation chip for the high-acuity device was sent for fabrication in August 2010. This chip contains flexible stimulation circuitry to excite the retinal ganglion cells, a power harvesting system and an integrated wireless transceiver. This transceiver operates in the Medical Implantable Communications (MICS) band, consuming less than 1mW of power. The team has also successfully demonstrated 50mW of power transfer in the air with a single coil design, which is within regulatory and surgical requirements and is very promising for the planned retinal prosthesis. Engineers have since designed and built a testing circuit board to assess the performance of the chip, in preparation for the first set of preclinical tests.
The team at the Melbourne Materials Institute, led by Professor Steven Prawer, continued to perfect the process for growing nitrogen dopedultrananocrystalline diamond (N-UNCD) that will constitute the stimulating components of the electrode array. Significant progress has been made towards electrically isolating individual electrodes, which is essential to enhancing the resolution of the images patients may perceive.
A prototype diamond case has been developed that will join with the electrode array along their perimeters, with the implantable electronics inside. The case will be hermetically sealed and biocompatible. This encapsulation approach keeps high temperatures localised and away from the chip to prevent damage.
Prof Stan Skafidas (NICTA and University of Melbourne)
Program Leader, High-Acuity Device Development
“The technology being developed for the high-acuity device is extremely innovative – if successful, it gives us the potential to leapfrog our international competitors.”
The Stimulation Strategy team is working on developing the most effective and safe ways to stimulate the surviving cells in the retina, so electrical impulses can then be passed from the eye, along the optic nerve to the vision processing centres of the brain. This program brings together researchers from the University of New South Wales, the Bionic Ear Institute, NICTA and the University of Melbourne.
The interacting streams within the Stimulation Strategy Program are:
The in vitro and in vivo projects are providing structural and functional data on the effects of electrical stimulation in the retina. This will inform the strategies used to reliably and safely activate the remaining cells in the retina. This work involves close collaborations between the Graduate School of Biomedical Engineering (GSBmE) at the University of New South Wales, Prof John Morley’s group at the University of Western Sydney, Prof Michael Ibbotson’s group at the Australian National University and Prof Rob Shepherd’s group at the Bionic Ear Institute.
The computational modelling teams, led by Prof Anthony Burkitt at the University of Melbourne and Dr Socrates Dokos at the University of New South Wales, are simulating the effects of stimulation in a retina using data collected in the in vitro and in vivo projects as well as developing stimulation algorithms.
The development of a human psychophysics test system has begun in preparation for the first patients testing the wide-view device. This work is led by Prof Peter Blamey at the Bionic Ear Institute.
Within the vision processing project, led by A/Prof Nick Barnes, a navigation environment was completed in 2010 for testing simulated phosphene vision (what patients may actually see with the retinal implant). Some participants with healthy vision have already been tested using a wearable, mobile virtual reality kit and specially developed navigation software, with promising results showing a stable representation of the environment. A prototype face zooming device has been developed and tested with a low vision patient in collaboration with the Clinical Program.
Prof Nigel Lovell (UNSW)
Program Leader, Stimulation Strategy
“We hope that this technology will restore patients’ ability to recognise obstacles, help navigate their surroundings and perhaps give them the ability to read simple text.”
The Preclinical research team is working on demonstrating the safety and efficacy of retinal implants prior to the application of these devices in the first tests with patients. Predominantly, this program is based at the Bionic Ear Institute, but also involves researchers from the Australian National University, the University of Melbourne and University of Western Sydney.
In collaboration with the Surgical Program, the placement of electrodes in the suprachoroidal space has been optimised in a series of acute and chronic implantation studies. These studies have established the safe distance from the optic disc of a suprachoroidal electrode array to prevent inducing retinal folding. Further, they have provided key information about the safe size and mechanical characteristics of a suprachoroidal array.
An initial biocompatibility study of diamond for the high-acuity device has been completed and studies attempting to stimulate retinal neurons, using fine nitrogen-doped diamond electrodes, have commenced.
The Preclinical Program has developed light microscopy histology techniques for the human eye as well as the hardware and software to automatically measure electrode impedance of up to 100 electrodes a minute. Electrophysiology techniques to perform acute experiments recording multichannel responses (maximum 98 channels) from the visual cortex to electrical stimulation of the retina have also been developed and tested.
Prof Rob Shepherd (Bionic Ear Institute)
Program Leader, Preclinical Program
“Success in developing any implantable bionic technology is based on careful, multidisciplinary research to ensure that patients ultimately receive safe and effective devices.”
The Clinical research team is working on establishing clinical tests for appropriate selection of patients, assessing and monitoring eye health, visual performance and vision-related quality of life at pre- and postimplantation. This program is based at the Centre for Eye Research Australia.
The clinicians at the Centre for Eye Research Australia are developing a database of patients with various degrees and durations of retinitis pigmentosa (RP), age-related macular degeneration (AMD) and other retinal degenerations. These patients are being recruited through Retina Australia, referrals from ophthalmologists and BVA website enquiries to participate in a series of visual function studies, which began in October 2010. The results from this initial clinical study will guide the development of a selection protocol for the first retinal implant patients.
The clinical team began work in 2010 to develop and validate tests for assessing visual function, daily living tasks and vision-related quality of life in patients. These tests will be used to assess the efficacy of the retinal implant in the first patients.
The Royal Victorian Eye and Ear Hospital has committed space for CERA’s BVA projects, specifically in the area of patient assessment.
During 2010, Dr Sharon Haymes undertook a two-month Churchill Fellowship in which she visited low vision research groups in Europe, Japan and the USA. She met with researchers in international bionic eye development teams to discuss patient assessment and training post-implant.
Prof Robyn Guymer (Centre for Eye Research Australia)
Program Leader, Clinical and Surgical Programs
“Australia’s first bionic eye could change the lives of millions of people world-wide who suffer from irreversible vision loss and blindness.”
The Surgical research team is developing new surgical procedures and equipment for implantation of the wide-view and high-acuity devices and will lead the first patient tests of the wide-view device. This program is based at the Centre for Eye Research Australia and the Royal Victorian Eye and Ear Hospital.
The Surgical Program works closely with the Clinical, Preclinical and Device Development Programs to provide surgical support for the safety and efficacy studies as well as carrying out clinical assessments of eye health following implantation.
Surgical studies in 2010 focused on assessing the feasibility of the electrode design and fabrication as well as optimising the placement of the electrode array within the eye for both the wide-view and high-acuity retinal implants. Surgical techniques are being developed using cadaver studies.
The use of x-ray guided surgery in 2010 has allowed surgeons and developers to observe the stresses on the device during implantation and the first study clearly demonstrated the degree of flexibility in the tip of the electrode array.
Dr Penny Allen
Vitreo-retinal Surgeon
“The surgical team are working hard to develop safe, reproducible strategies to implant the devices with minimal trauma to the tissues of the eye.”
2.2 Проект Artificial Retina Project
2.2.1 Общая информация о Artificial Retina Project
The DOE Artificial Retina Project is a multi-institutional collaborative effort to develop and implant a device containing an array of microelectrodes into the eyes of people blinded by retinal disease. The ultimate goal is to design a device with hundreds to more than a thousand microelectrodes. This resolution will help restore limited vision that enables reading, unaided mobility, and facial recognition.
The device is intended to bypass the damaged eye structure of those with retinitis pigmentosa and macular degeneration. These diseases destroy the light-sensing cells (photoreceptors, or rods and cones) in the retina, a multilayered membrane located at the back of the eye.
The DOE project builds on the foundational work of its leader, Mark Humayun at the Doheny Eye Institute of the University of Southern California. In a breakthrough operation performed in 2002, a team led by Humayun successfully implanted the first device of its kind—an array containing 16 microelectrodes—into the eye of a patient who had been blind for more than 50 years. Since then, more than 30 additional volunteers around the world have had first- or second-generation (60-electrode) devices implanted. These devices enable patients to distinguish light from dark and localize large objects.(Рис. 16)
Рисунок 16. Статистические данные и план работы проекта
Achieving the quantum improvements in resolution needed for useful vision requires the integration of revolutionary technologies such as those developed at DOE national laboratories. In 1999, the Doheny group began collaborating with researchers at DOE’s Oak Ridge National Laboratory, who also were working on approaches for restoring sight to the blind. Shortly thereafter they began to evaluate technologies at several other national laboratories as well.
To speed the design and development of better models, in 2004 Doheny and DOE (including six of its national laboratories), two additional universities, and Second Sight™ Medical Products, Inc. (a private-sector company), signed a Cooperative Research and Development Agreement. Under the agreement, the institutions jointly share intellectual property rights and royalties from their research. This spurs progress—freeing the researchers to share details of their work within the collaboration.
DOE supports the design, construction, and some preclinical (nonhuman) testing of the devices. Funding is for research in the following areas:
Over the past several years, the DOE Office of Science project has grown from a pilot funded at $500,000 (FY 1999) to a full-scale effort with current support of roughly $7 million per year.[6]