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Low Vision Aids for
Computer Users

By Liz Segre; updates by Marilyn Haddrill and Gary Heiting, OD

In general, visually impaired people can use the same low vision aids for viewing a computer screen as they do for regular reading activities. These include eyeglass-mounted magnifiers, handheld magnifiers and stand-alone magnifiers.

But also, special software has been developed to either display computer data in large print or read the material aloud in a synthetic voice.

These adaptive low vision devices let partially sighted people do the same computer-related tasks as fully sighted people — such as word processing, creating and using spreadsheets and viewing Web pages online.

Most computer operating systems and Internet browsers allow you to increase the size of Web pages and text on your computer screen to make them more visible to partially sighted users.

Here are a few simple tips for adjusting text size:

• In browsers such as Microsoft's Internet Explorer and Mozilla's Firefox, you can enlarge text on your screen by holding down the Control ("Ctrl") key on your keyboard and tapping the "+" key. (If you use Apple's Safari browser, use the Command key instead.)
• To return the text to its normal size, tap the "-" key while holding down the Control (or Command) key.
• You also can hold down the Control or Command key, then use the wheel on your mouse (see below) to increase or decrease the text size on your screen.
• Still another way to enlarge text on your screen is to use the "Text Size" or "Make Text Larger" command within "View" in the drop-down menu bar that appears at the top of your screen when you use popular software programs such as Microsoft Word and Outlook. On a Mac, the View menu has a "Zoom" option to enlarge text in Word and other applications.

Below are two images of a Google search page, as viewed in Safari version 4.0.5. In the top image, the text zoom is set at 100 percent. In the bottom image, the text zoom is set at 200 percent.

Large-print display software goes the extra step and displays not just larger text, but also icons, mouse pointers and other navigation items at larger sizes.

Another option is to use a screen magnifier placed in front of your display. But with the prices of LCD displays coming down, you might instead consider purchasing a larger display that's 19-24 inches with a diagonal measurement.

Voice Computer Systems

People with tunnel vision from glaucoma or central blind spots from macular degeneration may find it difficult and tiring to read an entire computer screen. This is one reason that "talking computers" were invented.

Talking computers are based on optical character recognition (OCR) systems that first scan text in a word processing document or Web page and then convert the text to sounds. The result is a synthetic voice that reads aloud not only the actual text but also important navigation items such as the cursor location. Voice systems are available from several major software companies.

Your Mouse

Some people with low vision prefer using keyboard commands instead of a mouse, because impaired vision can make it more much difficult to precisely position the cursor on the screen with a mouse.

Telesensory's Genie Pro offers a split screen so you can view your magnified image and your computer monitor's display at the same time.

Making the effort to memorize those keyboard commands may help you work faster at the computer, with less frustration.

If you would rather use a mouse, you may want to invest in one that is ergonomically designed for comfort and ease of use.

A wireless optical mouse is another good option, because your movements aren't limited by the wire leading from the mouse to the computer. If you sometimes experience hand cramps, try using a bigger mouse that lets your hand stay in a more open position, instead of clenched up.

A common source of frustration is a mouse set at a speed that is too fast or too slow. If you're a Windows user and you can't control your mouse because it seems to "zoom" across the screen, you can adjust this by clicking on the Start menu, then Control Panel, then Mouse. There you'll find all kinds of mouse behavior settings, including the pointer speed.

Glare and Contrast Adjustments for Low Vision

If you have low vision, you should consider using higher contrast settings on your computer screen. You'll find appropriate settings this way:

1. Select Control Panel on your PC.
2. Open the Display Properties dialog box and choose Appearances or Settings.
3. Under the Appearances and Themes tab in more modern software, select the High Contrast option.
4. Under Control Panel in modern software, you also might have a tab for Accessibility Options containing tips for low vision adjustments.

If you have a Mac, select System Preferences and then Displays. You'll then find options for adjusting screen resolution to increase contrast and to change the appearance, which allows you to select colors.

Dark text displayed against light backgrounds generally is considered the best color combination for those with low vision.

To reduce glare on your computer screen, make sure you close curtains to prevent reflections from outside lighting. Also, try adjusting the position of your computer screen to reduce glare. Special screens and hoods are available to fit around your computer screen to maximize visibility.

Flickering Screens and Other Problems

If you are using an older desktop computer with a tube-style display (also called a cathode ray tube or CRT) and you notice the screen "flickers," be aware that this can cause computer eye strain.

Usually you can eliminate the flickering sensation by adjusting the CRT display settings. If you use Windows, go to the Display menu within Control Panel. Click on the "Advanced" tab and adjust the refresh rate of the screen to 70 Hz (hertz) or higher. This should eliminate the flicker and increase viewing comfort.

Modern liquid crystal display (LCD) screens create images using different technology and don't cause flicker problems. Therefore, these "flat panel" displays tend to be more comfortable for long-term viewing and cause less eye strain than CRT screens.

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[Page updated April 2010]