These work like a magnifying glass. They enlarge a portion of the screen as the user moves the focus - increasing legibility for some users. Some screen enlargers allow a user to zoom in and out on a particular area of the screen

These are software programs that present graphics and text as speech. A screen reader is used to verbalise, or 'speak' everything on the screen, including names and descriptions of control buttons, menus, text and punctuation.

Also called voice recognition programs, these allow people to give commands and enter data using their voices rather than a mouse or keyboard

Often referred to as text-to-speech (TTS) systems), these receive information going to the screen in the form of letters, numbers and punctuation marks, and then 'speak' it out loud. Using speech synthesisers allows blind users to review their input as they type.

This display provides a tactile output of information represented on the computer screen. The user reads the Braille letters with his or her fingers, and then, after a line is read, refreshes the display to read the next line.

These transfer computer-generated text into embossed Braille output. Braille translation programs convert text scanned in or generated.

These are software programs that use speech synthesisers to provide auditory feedback of what is typed.

These allow the user to view everything in large text without added screen enlargement.