Assistive Technologies for users with Low Vision

From Low Vision Accessibility Task Force

Assistive Technology - Software

ZoomText

ZoomText is a screen magnifier and reader for Windows.

MAGic

MAGic is a screen magnifier and reader for Windows.

Global Public Inclusive Infrastructure (GPII) and Cloud4all

  • Global Public Inclusive Infrastructure (GPII) is a software and service enhancement to broadband infrastructure.
  • Cloud4all is an international project with objectives of "Simple Instant accessibility for ALL", "Anywhere Any Device Access", "Supply and Demand better connected", and "Affordable method to offer diversity needed".

Use Case Video

  • Alicia's Story - "...Alicia is a 70 years old pensioner living in a house for the elderly. Additionally, she suffers some sort of visual impairment. Even though she is willing to catch up with the current world news, Alicia sometimes has problems due to her special needs when surfing the web. She requires a high contrast and a big font size at least in order to navigate easily. Nonetheless these settings are not easy to adjust, therefore every time she uses a computer, she needs help for that. Here is where magic happens with Cloud4all and GPII due to the fact that only by keying-in a USB pen-drive all these adjustments are made automatically without the need to seek external help..." Cloud4all

Access to Visual Presentation

A visual presentation that is highly usable for people with normal sight is usually difficult or impossible for people with low vision. Whenever possible a mechanism to transform the author's presentation into the user's preference is the best assistive technology for visual reading with low vision.

The Customized Assistive Style (CAS)

Whenever possible I create a style sheet to present my reading content in a form I can read. These style sheets adjust typographic metrics that are well known to influence readability for people with my disability, central vision loss. The metrics are: size, spacing, color, font face, line length and polarity. I have designed these style sheets so that changing a few settings is all that is needed to make the style sheet usable by others. CAS Objects

Definition A customized assistive style (CAS) object is a specification for the presentation of a document that has accessibility support from a user agent and creates a typographic environment that matches the preferences of an individual with a print disability.

Unlike my style sheets, the CAS object is a broader class of object. My assistive style sheets are certainly an exemplar, but they are not the only category in CAS. When I use a word processor I write a few document templates. When someone gives me a document I cannot read, I just insert it into one of my template based documents. If the author used fairly generic document objects in their document then my template will convert the original presentation into one I can use. These word processing templates are CAS objects. Not all document file formats or user agents can support CAS objects. However, whenever a CAS capability exists this is by far the quickest and most helpful way to create a usable presentation.

What's in a Name

When I use the term like customized assistive style object, most web professionals think I am referencing user style sheets. This is not the case. I am referencing any mechanism that can be used to communicate the presentations preferences of a user to the user agent for a document she may not have created, but hopes to use. A user style sheet can be a CAS object, but it must be constructed to be an assistive technology to qualify. The stated presentation requirements of an actual user with a print disability must be supported by a style sheet for it to be CAS. The CAS object is usually developed by a professional for use by people with print disabilities.

The term user style sheet is just too pejorative. It connotes a level of unprofessional authorship that is inconsistent with the serious purpose of assistive technology. This sloppy name enables those who do not want to consider CAS as a serious assistive technology to marginalize it. To escape this unprofessional labeling, I have coined the term CAS object to differentiate style transformations that are assistive technologies from style sheets that are used for other purposes.

Resistance

Many people do not want to admit that technology like CAS is necessary. In the disability support community many consider the CAS approach to be unnecessary. I am frequently pointed to the efficacy of professional screen magnification systems. This enthusiastic endorsement of screen magnification rarely comes from somebody who actually uses the technology to read. Many people use screen magnification systems like I do, when nothing else is available. For my part, these systems do not reach the threshold of reasonable accommodation. Truncated lines with horizontal scrolling is the obstacle for me, as it is for almost everyone. Some people can read effectively with horizontal scrolling. I am not one of them. I have tried. I just cannot read serious content that way.

Many stake holders in the web do not want to enable users to choose their own presentation. Graphic designers resist anyone tampering with their vision of a page. User agent producers resist the additional responsibility of providing mechanisms for user choice in presentation. Content developers are often ignorant of simple structural conventions that would support CAS solutions in their medium. Some content types are not capable of supporting CAS. There are even sites that check for attempts to change the presentation and redirect the user when a change attempt is detected. In HTML, some authors consciously or unconsciously sabotage assistive style sheets by including reserved symbols of CSS like ":" in ID values.

I believe the source of this resistance to CAS is a hesitation to accept that the current model of accessibility support is inadequate. Even though screen magnification is not effective for most people with partial sight, it fits the current mental model of how assistive technology should work. The current model for assistive technology is this: The assistive technology, sits outside of the actual application, a browser or other platform program. When necessary, the assistive technology interprets I/O through an accessibility API. That mental model supports screen readers and special input technologies like voice recognition, but there is real doubt as to whether this model can support the reformatting and visual rendering flexibility that is required for CAS. In addition, even if this model could be made to work, the success criteria of WCAG 2.0 might not be robust enough to support CAS.

I am somewhat agnostic about how CAS is implemented. If the current model of computing would work that is fine. If a new approach like add-ons for user agents worked that would be fine as well. I am convinced from experience that custom user style is a serious necessity for full integration of many people with low vision into reading and literacy. The fact that it may require significant change should not be a factor in declaring its appropriateness for supporting the people who need it.

Assistive Technology - Hardware

This content to be updated soon.

Assistive Technology - Mobile

Visor

Visor, a magnifier App for iOS. It is a "magnifying glass for your iPhone, iPad and iPod touch. Enlarge difficult to read text by 4 magnification levels and change contrast to 5 different viewing modes. Optionally, turn on the LED flash of your device to help you see better in low-light conditions."

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