Put your graphical user interface to this test: Adjust the contrast on your display until the screen is completely black.

Now, perform basic e-mail, word processing and Web-browsing tasks.

What? Having a problem?

Welcome to the world of the 1.3 million Americans who are blind. For them, the world of personal computers, office automation and the Internet offers mixed blessings. That world wasn't designed for them, but with the right assistive technology, they can take part in it. When everything works well, they have access to an ocean of information vastly greater than anything previously available to the blind. But pitfalls and maddening frustrations are a constant reality.

Screen readers

Blind computer users mainly rely upon screen-reader software, which describes the activity on the screen and reads the text in the various windows, explained Gayle Yarnell, owner of Adaptive Technology Consulting. Yarnell is blind.

Screen readers cost between US$500 and $1,000, although there are also freeware screen readers, she noted. (Windows XP and Vista come with a screen reader called Narrator, but even Microsoft says it's not powerful enough for serious use.)

The screen reader's output can be sent to the computer's speakers as a synthesized voice or to a Braille display. The latter uses tiny push pins to create a pattern of raised dots that can be read by a moving finger. A unit with an 80-character line (enough for one full line of text) costs about US$10,000, and Yarnell said that most blind people use a 40-character unit, which costs closer to US$5,000.

Braille displays are better than speech for editing because individual characters can be isolated, she noted, and they are a necessity for the deaf-blind. She also said that it lets her silently read e-mail while talking to someone else.

Although major operating systems usually have built-in screen readers for accessibility by the blind, they are rudimentary at best. In fact, after starting Narrator, the screen reader that comes with Windows XP and Vista, Microsoft's introductory screen says, "Most users with visual impairments will need a screen reader with higher functionality for daily use."

But knowing what the screen is saying is just the beginning -- the blind user then has to issue commands using keyboard shortcuts, because the mouse cursor is useless. Using shortcuts involves a lot of memorization, but at least the option is always available -- or at least it used to be.

"Starting with Version 3.1, Microsoft tried to make sure there was a keystroke to do everything in Windows," noted Dave Porter, an accessibility consultant and head of Comp-Unique. "But with Vista, we seem to have lost that thread." The main problem is that, with Vista, the effect of a keystroke depends on the situation about a third of the time. Also, there are things that simply can't be done with keystrokes, said Porter, who is blind.

"It's not so much that the keyboard shortcuts are different but that the user interface has changed," said Rob Sinclair, director of accessibility at Microsoft. "We have gotten away from a lot of menus and created a more simplified experience. No one would argue that there is no learning curve, but we have seen value and heard great feedback from those who have taken the time to learn the new version.

"There are some amazingly powerful features in Vista for those with disabilities, like a Start function that begins with a search field," Sinclair added. "You can type in the name of an application, or a command, or search for a keyword in a document or an e-mail. You can launch any application with a few keystrokes, easier than using menus." He also noted that the latest version of Microsoft Office still supports the old shortcuts.