3. Visual Impairments

There are two categories of visual impairments. Individuals who are partially sighted (for example, blurred vision, near and far-sightedness, color blindness) and those who are totally blind. Assistive technologies are available for the Linux operating system for visually impaired users, and many of the software packages are free.

3.1. Technologies for the Visually Impaired

The following is a list of assistive technologies for visually impaired users:

3.1.1. Screen Readers

Screen readers are software applications that are installed on the computer to provide translation of the information on the computer screen to an audio output format. The translation is passed to the speech synthesizer and the words are spoken out loud. Currently, fully functional screen readers are only available for Linux in console mode. This section describes some of the most common screen readers.

3.1.2. Speech Synthesizers

Speech synthesizers can be a hardware device or a text to speech (TTS) software application that creates the sounds necessary to provide speech output. Hardware synthesizers are available for the Linux operating system; however, they can be very expensive and must be compatible with the screen reader application in order to function properly. The alternative is to download and install a software synthesizer such as IBM's ViaVoice or Festival and configure the application to a compatible screen reader, such as Emacspeak.

3.1.3. Screen Magnifiers

Screen magnifiers enable users that are partially sighted to view selected areas of the screen in a manner similar to using a magnifying glass.

3.1.5. Braille Devices

Braille terminals are normally used by individuals who are totally blind and may be hearing impaired as well. A Braille display uses a series of pins to form Braille symbols that are continuously updated as the users changes focus. A Braille embosser is a hardware device for printing a hard copy of a text document in Braille. Braille translation software is required to translate the on-screen text to a Braille format. Braille Hardware Devices

The following Braille devices have been listed on the hardware compatibility list of one or more of the following Braille translation applications: Braille Translation Software

The following Braille translation applications are available for download:

3.1.8. Additional Resources