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 display content on the screens of computers and other digital devices in large print. Other applications can read text and other visual content aloud with 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.

Screen magnification

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 most browsers on a PC you can enlarge a web page on your screen by holding down the Control ("Ctrl") key on your keyboard and tapping the "+" key. (If you use a Mac, hold down the "Command" key while tapping the "+" key.)

• To zoom out, tap the "-" key while holding down the Control key (or Command key).

• To return the view to actual size, tap the "0" (zero) key while holding down the Control or Command key.

• Some devices, browsers and applications also offer the ability to enlarge text and images with a "Zoom" command in the View menu at the top of the browser window.

Third-party screen magnification software goes the extra step and displays not just larger text on your screen, but also larger icons, mouse pointers and other navigation items. Products such as Zoom Text, SuperNova Magnifier and MAGic will enlarge the text and images on your screen.

Also, a person with low vision will benefit most from these options for magnifying print and images when using a desktop computer with a large screen size (21 inches or larger).

Screen reader programs

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 powered by screen reader software 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.

With screen reader programs even totally blind people can use a computer because they convert both text and icons to speech. Some screen reader options include: MAGic LVS; Serotek System Access To Go; SuperNova Screen Reader; and ZoomText Magnifier/Reader.

Another option is a simple built-in screen reader called Narrator that is included with Microsoft applications.

If you use Google's operating system, it includes a screen reader called ChromeVox. If you are a Mac user, Apple includes a screen reader called VoiceOver.

If you have some functional vision, but sometimes struggle with reading certain text, a simple screen reading program may do the trick and will likely be easier to learn, since you merely select the text you want to be read aloud. Panopreter, Natural Reader and ReadSpeaker Text Aid all offer this type of functionality.