The two main computer accessibility tools are screen magnifiers and screen readers. If you have little to no usable vision you will be best served with screen reading software, which reads aloud all of the text and text-based elements displayed on a computer screen. If you have some usable sight, you might find screen magnification software, which enlarges the information displayed on a computer screen, helpful on its own or used in concert with a screen reader.
Built-in versions of screen readers and screen magnifiers are included on both OS X and Windows 7 and 8.1 computers. In addition, there are both free and paid options available that we will discuss later in this guide. First, let's take an introductory look at how these programs help users with visual impairments use a computer.
Screen Magnification Software
The most basic task of screen magnification software is to magnify the screen. Some screen magnifiers enlarge text, icons, and other graphics up to 20 times or more. If you are typing an e-mail while using a screen magnifier, for example, the program will enlarge the words you type to make them easier to read. As you type characters, issue keyboard commands, or move your mouse, a magnified screen view will keep up with what you are doing and where you are focused on the screen.
Screen magnifiers can also enlarge and enhance mouse and text cursors to make them easier to see and track. Magnifiers can also sharpen edges, increase contrast, and change color combinations to make things easier to see.
Since vision acuity differs from person to person, screen magnifiers give users many options to customize what to magnify and what to highlight or sharpen. You’ll probably spend considerable time at the beginning optimizing various settings for your particular needs, but this is a one-time chore. Once you save your settings they will be available anytime you use your computer.
Screen Reading Software
Screen readers speak letters, words, numbers, punctuation, and elements aloud, sending the voice output to your computer speakers or connected headphones. Screen readers are the default computer access method for people who are unable to see the computer screen. Even users with partial sight will want to learn about, and most likely use, screen readers. Perhaps right now you can operate a computer perfectly fine with just a bit of screen magnification, but what if your vision deteriorates? Even if your functional vision remains steady, pairing a screen reader with a screen magnifier will enable you to spend more time using your computer with minimal eye strain.
Screen readers use one of a growing number of computer voices, also called text-to-speech engines, to speak text. You’ve probably already heard these voices in use on phone trees and the US Weather Bureau forecast cable weather channel, and in airport gate announcements and TV commercials featuring the Apple Siri voice. The voices are usually customizable, giving you the ability to set volume, pitch, tone, and speed. You can start out with a slow voice, then, as you grow accustomed to the program, speed it up to the point where you may be able to read text faster than a computer user with sight.
Of course a screen reader must do a lot more than simply read the computer screen. As you enter data, click links, or issue other commands, the computer screen changes. If you had to wait for the software to read the full screen each and every time a single letter or graphic changed, you would never get much done. That’s the "special sauce" in these software programs: screen readers use a bit of artificial intelligence to determine what information you may wish to hear at any given time. Full-feature screen readers include dozens of screen reader keyboard shortcuts that will read highlighted text, characters, words, paragraphs, and any number of other text elements. Screen readers can announce each keystroke as you press it, decode and describe icons, and even describe certain graphic images. Screen readers also include special mouse navigation keys that allow you to manipulate the mouse pointer, moving it wherever on the screen you like, and to press other keys to perform a mouse click or double click.
If you are learning to read and write braille, most screen readers offer an additional useful option. Instead of having your screen read out loud, you can obtain a refreshable braille display and use your screen reader without audible speech.
Before taking a closer look at screen readers and magnifiers, let's talk about the importance of keyboarding and typing skills for accessible computing.