Sabtu, Februari 28, 2009

Visually Impaired Users - How To Help Them - Accessible WebDesign

 

Visually Impaired Users - How To Help Them

Introduction

A fairly large percent of Internet surfers are visually impaired. Whether members of this group are blind, colour blind or do not have the vision they once had, it's important their needs are recognised.

The point of this article is to bring awareness to web designers about the importance of making web sites accessible, aiding visually impaired users and the HTML guidelines to creating a universal design solution.

Visually impaired users represent a large part of the Internet community who use online services such as online shopping, or online banking. Web applications and web sites should take into account visually impaired users as well as those with 20/20 vision.

Identifying the audience - Issues to address

Before proceeding the web designer (or web developer team) need to know exactly what sort of audience a certain site has. By identifying difficulties they can make significant changes to suit that specific audience and make the web site more accessible to them.

People with visual difficulties:

  • May be colour blind.
  • May be completely blind or partially sighted.
  • May suffer from disabilities preventing them from reading or comprehending text properly (for example dyslexia).
  • May not be able to read small text - a large segment of the population could be affected.

The web designer has to keep all these issues in mind when designing a web site to suit certain needs and standards. There are several alternate browsing methods used by the visually impaired to make Internet browsing more comfortable and enjoyable.

Browsing alternatives for visually impaired users

Over the past few years, some browsers have been developed especially for people with disabilities. These include products with optical character recognition, screen magnifier, screen readers, voice recognition, speech synthesisers, etc. Below are only some of them

  • Braillesurf - BrailleSurf is an Internet browser for visually impaired users, which allows a simplified reading of the information available on the Web. BrailleSurf 4 shows this information in a text form. This information can then be displayed on a Braille bar, or it can be spoken out by a speech synthesiser. The text can also be presented on the screen according to the needs of partially sighted people.
  • BrookesTalk - BrookesTalk is a under development by Oxford Brookes University and is a function key driven Web Browser for blind and visually impaired users, providing keyboard only accessibility using the function keys. It also provides a configurable large text window for partially sighted users and a standard visual browser so that users can work together with sighted workers. Quick views of web pages are provided using information retrieval and natural language processing techniques.
  • ALVA Braille - Offering screen readers and Braille displays. A screen-reader is used to allow navigation of the screen presented by the operating system, using speech or Braille output.

Is there still need for intervention in a web site design?

We've established the fact that there are tools and software on the market to help the visually impaired in surfing the Internet. The question now arises, is there still need for the web designer to tweak and improve the design for this particular group?

Poor design is the biggest impediment in alternate browsing

Browsers and tools developed for disabled people read the source code of the web page and then render it in the way they were designed: either Braille output or speech output. If the web page is poorly constructed the alternate browser will encounter difficulties in interpreting it correctly and prevent the web page from making sense to the user. This is where the web designer has a crucial role.

Validate the code of your website

Using standard HTML syntax means avoiding important errors that could appear in the source code. Syntax errors prevent interpretation of the source code by alternate browsers and make it difficult to the user to take in the information.

Using tables requires extra care

Considering the way table cells and rows are actually written in the source code, it's important to make sure that a source code interpreter extracts the information in the order it was meant to be read. For example, including text in vertical columns instead of rows can create confusion because the source code first displays the cells in a row before reading the second column cell. Severe gaps could appear in the natural information flow.

ALT and TITLE as descriptive elements

Because visually impaired users are often unable to see pictures, they rely heavily on the description associated with them. ALT tag for images and TITLE tag for other elements have become increasingly important in order to fully describe all elements of a web page.

Using less graphics is more for all users

Using graphics intensive interfaces for the web may work for the average Internet user but the visually impaired person has no ability to fully retrieve the message transmitted by graphics, even by using an ALT tag. Using less graphics not only reduces load time for all your users but may prove to be less stressful and distracting to the average user as well as the visually impaired.





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