Screen Readers for Blind Users
Screen readers provide an audio version of information that appears on a computer screen. They use keyboard commands to substitute for mouse use, and read almost everything on the screen, including menus, dialogue boxes, etc.
This article covers both free and third-party commercial screen readers designed for use by blind people, and will help you get started.
Programs designed for use by sighted people with learning or cognitive disabilities are covered in the article "Text-to-Speech Readers for People with Learning Disabilities."
Most screen readers are highly customizable, so that users can specify preferences such as whether punctuation is read, how fast the program speaks, or whether cues helpful for new users are spoken.
A video introduction to how blind people use screen readers is available online.
A simple screen reader called Narrator is included in Windows operating systems. Most commercial Windows screen readers are expensive; however, there are now free third-party screen readers that will be sufficient for many users' needs. Macintosh computers have a full-featured screen reader called VoiceOver built in to the operating system.
Try It Yourself:
Windows XP: Go to Start Menu-->All Programs-->Accessories-->Accessibility-->Narrator.
Windows Vista and 7: Go to Start Menu-->All Programs-->Accessories-->Ease of Access-->Narrator.
Macintosh OS X: Apple Menu-->System Preferences-->Universal Access-->Seeing and choose the "On" radio button next to VoiceOver, or simply press Command (cloverleaf)-F5 to toggle VoiceOver on and off.
Third-Party Screen Readers
Commercial screen readers work with a wide range of applications and are highly customizable. The most popular of these are JAWS from Freedom Scientific, Window-Eyes from GW Micro, and SuperNova from Dolphin Systems. All of these have demonstration versions available that can be downloaded from the manufacturer's website and tested for a limited period of time. Since experienced screen reader users tend to be loyal to a specific product, it is worthwhile finding out what blind individuals in your community already use; this should weigh heavily in any purchase consideration.
Because commercial screen readers as much as a thousand dollars, there have been several initiatives in recent years to create and distribute free screen readers that work with a limited number of applications. These usually also have an option to purchase a higher-quality version with better voices, but these are still significantly less expensive than the commercial products. Some, like NVDA, are downloaded and used like commercial products; others, like System Access to Go, work through the Internet.
The American Foundation for the Blind has a series of questions to consider when purchasing a screen reader, adapted here for relevance to public computer labs:
- Is the screen reader compatible with your computer’s operating system? Does it work with most or all of the mainstream applications you offer to the public?
- If you provide refreshable braille hardware, is it compatible with the screen reader?
- Can it read a word, line, and paragraph of text?
- Do its commands conflict with Windows keyboard commands?
- What keystrokes are used for the program’s basic and advanced functions? Are the keystrokes easy to remember? Is it possible to change the key combinations if they conflict with those used by application programs?
- Do your patrons need high-quality speech, which is more expensive, or can they function comfortably and efficiently with lower quality speech? (For example, if many of your screen reader users are older, they may need high-quality speech to compensate for aging-related hearing loss.)
- Does the synthesizer mispronounce many words? Can you listen to it comfortably for more than 15 minutes without getting a headache?
For blind individuals who need or prefer to use refreshable braille instead of audio output, most screen readers can also be used to run refreshable braille devices.
Although screen readers are very powerful programs, they can not always provide equivalent access. This is particularly true for websites that have been set up in a way that screen readers cannot interpret. Web accessibility guidelines provide extensive information on making websites compatible with screen readers and other assistive technologies.