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Technical Developments for People with Visual Disabilities

John Gill



Technology is fast becoming an essential tool for individuals who want to fully participate in modern society.  It is not just access to computers and the internet, but includes the use of self-service terminals such as ticket machines at railway stations.  The convergence of computing, telecommunications and broadcasting has been talked about for many years but is now a reality.  This has introduced a number of new problems for people with disabilities.

The general approach has been to design equipment for the general public so that it can be used by as many people as is reasonably possible – this is often referred to as ‘inclusive design’.  However this will not cope with all types of disability in all circumstances so it may be necessary to provide an interface to an assistive device (eg a signal which can be picked up by the inductive coupler in a hearing aid).  Even this approach will not resolve all issues so it may be necessary to provide special terminals but this is an expensive solution.

Assistive Technology

Traditionally assistive devices were single purpose gadgets which were only used by the target group.  There were some notable exceptions – the fountain pen, typewriter and long-playing record were all originally developed to help blind people but were only economically viable because sighted people found them to be useful.  The commercial organisations involved in the development of assistive technology have tended to be risk adverse and prefer to develop a new model of an existing product rather than take the risk of developing a new concept. 

In recent years the main effort has been devoted to providing access to computer systems including the internet.  Significant improvements have been made to screen readers, but the main beneficiaries have been blind people in employment or education.  Some effort is now being devoted to transferring these products for use them with smart phones, but consideration will need to be given as to how to train and support individual users.  In the foreseeable future, electronic vision systems will be developed to prototype stage, and some may make the transfer to being a product available at affordable prices.

For many years scientists have addressed the problem of how to use electronic systems to replace some of the functions of the human eye.  Up to recently these were just interesting laboratory experiments, but new developments in electronics and wearable computers could turn these prototypes into devices of practical benefit at affordable prices.

The three main approaches are:
•             Vision enhancement
•             Vision substitution
•             Vision replacement

Vision enhancement involves input from a camera, processing of the information, and output on a visual display.  In its simplest form it may be a miniature head-mounted camera with the output on a head-mounted visual display (as used in some virtual reality systems).

A more sophisticated system might have a combination of visual and ultrasonic cameras.  The ultrasonic camera can provide information about the distance of an object from the camera.  The user could then instruct that he or she is only interested in viewing items less than 2 metres away.  The processor would then delete all data more than 2 metres; this would significantly reduce the clutter on the visual display.

Another possibility could be that the user is looking for a post box which he knows is painted bright red.  He could request that anything which is not red is shown with lower brightness.  Yet another possibility is for the user to instruct that only the edges of objects should be displayed.  There are many other possibilities for processing the information to meet the specific needs of an individual at that moment.

Vision substitution is similar to vision enhancement but with the output being non-visual – typically tactual or auditory or some combination of the two.  Since the senses of touch and hearing have a much lower information capacity than vision, it is essential to process the information to a level that can be handled by the user.

Vision replacement involves displaying the information directly to the visual cortex of the human brain or via the optic nerve.
Vision enhancement systems have already appeared on the market, but significant improvements can be expected in the next few years.  Vision substitution systems already exist, mainly as developments of electronic mobility devices, but it is likely to be some years before they come into widespread use.  They will need to be accompanied by appropriate training.

Affordable vision replacement systems are farther into the future since much more needs to be known about how to optimally connect to the visual cortex.  Since this will involve a surgical procedure, there will need to be stringent testing to ensure that there are no adverse effects.

Over the next few years it will be important to differentiate advertising hype from the real benefits to some people from the appropriate use of these systems.  There is a tendency to dismiss developments if they do not live up to the stories in the newspapers, but it would be unwise to dismiss these systems even if claims are made that they “solve the problems of blind people”.

Electronic vision systems are not the only new types of assistive technology which could benefit blind and partially sighted people but the business case is often difficult to justify to get a novel product into a market to which it is difficult to communicate.

Mainstream Technology

The pace of development of new technological devices means that the development time for a new product has been cut to a minimum, and the shelf life of the resulting product may be measured in months not years.  Often the design is done by using simulation software with no hardware prototype being built before the production model.  This means that any accessibility issues have to be considered without the possibility of evaluating prototypes with a range of users with various disabilities.

The mobile telecommunication area is the one with the greatest pressure to get new products to market even if that means leaving consideration of accessibility issues to be fixed retrospectively. This often means that accessibility improvements are limited to those which can be implemented by software alone.

There are a number of exciting areas of research which could potentially be of great benefit to people with disabilities.  One such area is ambient intelligent systems in which various systems can autonomously communicate with each other.  Such systems are claimed to be:

To engineers ambient intelligence offers true integration and is their utopia.  However for a privacy expert this scenario is their nightmare.  What a scientist thinks of as ‘ambient intelligence’ may soon become muddied by marketing departments claiming their products are ambient intelligent but meaning something different from the scientists.

Cloud computing is another area where different people use the term to mean different things.  It is likely that more software and data will be held within the network, but often the user will be unaware that this is the case.  The possibility of holding assistive software, such as screen readers, in the network could ease the problems of disabled people when away from their home or office, and possibly reducing the cost of using such software.  Open source software also could mean lower costs for the consumer, but, as yet, the open source movement has not made much impact in Europe for people with disabilities.

For a long time there have been adapted user interfaces where, for instance, a user plugs in a special keyboard.  Adaptable user interfaces permit the user to select the features which they prefer (eg larger characters on a screen).  These preferences can be stored on the user’s card or in the network at the user’s request.  Although there is a European standard for the coding of these preferences, such systems have only been implemented in a few places.  In the longer term there is the possibility of adaptive user interfaces where the system automatically modifies the user interface based on the user’s behaviour; although these systems work in a laboratory setting, they have proved difficult to implement in real situations.

Will It Happen?

There are a large number of factors which affect the practical transfer of both assistive devices and accessible information and communication technology systems from the laboratory to being generally available at affordable prices.  In the disability area, the member states of the European Union have many different systems of supply and subsidies which makes the market far from homogeneous.

One problem is the lack of a systematic analysis and quantification of the unmet needs of people with disabilities. This means that commercial organisations find that the market for their accessible products is far from that which they had expected, since they had started without a full understanding of the issues faced by disabled people including the effects for those with multiple impairments.

The role of legislation and regulation is central to what reaches the market.  In the USA section 508 of the Rehabilitation Act requires government departments to procure accessible products.  In Europe a similar requirement is likely to be based on mandating certain standards.  The standards need to be in a form which does not limit future technical development whilst still being measureable so that compliance can be proven.

In Europe the provision of support services including training in the use of the systems and services varies from one country to the next.  It is often considered to be inadequate particularly for consumers with an intellectual impairment.

Accessibility of mainstream technologies could be improved by adopting inclusive design principles but, as yet, few companies have fully taken it on board.  Inclusive design needs to be considered at all stages of the design process and not just at the end (like adding a coat of paint).  There are many simple features which would improve the usability for everyone like appropriate choice of fonts, standard layout of function keys and consistent sequence of operations; however such simple features are often forgotten.  So it will not be a simple matter to persuade companies to incorporate accessibility features of practical benefit rather than just ticking the boxes required by legislators.


Dr John Gill can be contacted at


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