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Inside Adaptive Technology

Understanding some basics about adaptive technology helps you to better incorporate accessibility in cyberspace projects. As an information-driven society with a short attention span, we're accustomed to information being "just a click away." Sure, we all have carpel tunnel syndrome, but who cares! We have one-click shopping, searches, news, music, chats, research, and too many other things to count.

Enter the world of adaptive technology for visual impairment.

Information-driven? Yes, after all, we're all people who share similar interests, regardless of our ability to see. Is information a click away? No—far from it.

Screen Enlargers

Screen enlargers comprise that category of adaptive technology designed for people with low vision. An estimated 10 million people in the United States have low vision, consisting in large number of elderly folks. Pay attention; you will someday be part of our aging population.

People with low vision must have enlarged, high-contrast displays in order to view what is on screen. How large? Well, consider how large the Start button on a Windows-based computer would be if it took up 35% of the display (see Figure 1). That's how large a typical low-vision person views the computer world.

Figure 1 Looking at the computer world with a screen enlarger.

To give you another idea of how large this is, imagine viewing a Microsoft Word document. You would only be able to view three menu items at a time because they take up that much room horizontally across the screen.

Figure 2 Looking at the Microsoft Word menu with a screen enlarger.

With that in mind, the key feature to understand about screen enlargers is that only a small portion of the screen is visible at any given time. This means lots of scrolling back and forth just to read one sentence or view the next part of a word. Hyperlinks in Web pages aren't just a click away, and reading PDF files can be a challenge.

Web Pages

Let's go inside a Web site using a screen enlarger. Consider a fictitious news Web site, with characteristics that are typical of many Web sites. With extensive use of graphics, this Web site looks great and is informative with clearly defined navigation.

Here is more detail about this Web page: The main menu on the left side of the home page contains 17 menu topics, all created with a graphic rather then text. In addition, upon accessing the home page, a small pop-up window automatically appears with advertising information.

Now, take a look at just two problems encountered using a screen enlarger.

  • Pop-up advertising window: Sometimes you encounter an automatic pop-up Web window upon accessing a Web page. When using a screen enlarger, it's difficult to see that the pop-up window is present, as shown in Figure 3. However, the pop-up window remains in focus until dismissed, which can take time to figure out because you can view only a small portion of the screen at one time.

  • Figure 3 Automatic pop-up Web windows can be a hindrance when using a screen enlarger.

  • Graphic text menu: Although the navigational menu is clearly defined, graphics are pixilated when enlarged. The jagged edges of the text make it difficult to read when enlarged, as seen in Figure 4. Although you may be able to figure out the letters that make up a word, keep in mind that a low-vision person may not be able to.

Figure 4 Enlarged text images are quite difficult to decipher.

Although there are even more hindrances to Web navigation then I mentioned, hopefully these two simple examples give you a better idea of an Internet experience through screen enlarger software.

PDF Files

PDF files offer other challenges when using screen enlarger software. Let's take an example of a simple two-column PDF document that totals 10 pages. To make it simple, assume that no graphics appear on any page.

Here's an idea of you might encounter if this PDF file was created with no accessibility in mind.

  • Read order: In a two-column document, you read down the first column, continuing at the top of the second column. With enlarged text, both columns of a PDF document don't fit horizontally onscreen. With screen enlarger software, you would begin reading at the beginning of the document and press the Enter key on the keyboard when you are ready for the next part of the document. The next bit of information is now in view. You can keep pressing the Enter key to go through the entire document in this way. The problem is if the PDF is not made accessible, page 2, column 1 is displayed rather than page 1, column 2 when you reach the bottom of column 1 and press Enter.

  • Reflowing text: Sometimes, it's easier to read text if the content is reflowed into a smaller-sized display window for viewing purposes. Otherwise, you end up with lots of side-to-side scrolling in order to see an entire line of text at one time onscreen. Acrobat has the capability to reflow text whether it be in one or two-column format, so it fits horizontally onscreen according to the width of the window. This makes for much easier reading.


You can read more about Adobe's PDF accessibility support at

These are just two small examples of how you might experience a PDF file using a screen enlarger. We often don't consider how everyone perceives our Internet creations. This is a good time to start.

Screen Readers

Screen readers comprise that category of adaptive technology designed for people with no vision, although some people with low vision find it helpful to use screen readers along with a screen enlarger.

With a screen reader, you have a very different experience of the Internet. Screen readers enable you to "listen" to the Web, converting text to synthesized speech using a special text-to-speech engine. The content of a computer screen is output through your computer's speakers.

Screen readers work with many popular software applications, such as Microsoft Word, Excel, PowerPoint, Explorer, and Adobe Acrobat, just to name a few. Keyboard commands are primarily used to activate controls and get around the screen.

Turn off your screen for a moment, turn on your speakers, and experience a screen reader.

Imagine: In Microsoft Word, you press the Alt key to change the focus to the menu across the top of the screen. The first menu item is the File menu. You hear the synthesized voice say, "File."

Press the Enter key, and listen to the voice say, "File menu open."

Press the down arrow key, and you hear the voice recite, "New," the first item in the File menu. Listen to the voice recite each File menu item as you continue pressing the down arrow key.

This scenario gives you an idea of what a screen reader computer experience might be like.

Web Pages

To give you an even better idea of how a person using a screen reader might experience your Web page, let's "listen" to a typical Web page.

Let's use the same Web page scenario that we used for the screen enlarger example. Remember, the navigation menus were created with graphics rather then text. In addition, a table appears on the part of the Web page with organized informational data.

  • Graphic menus: Because the menus are graphics rather then text, this Web site is useless for a person using a screen reader. If the creator at least includes alternative text tags for each graphic menu item, the screen reader can easily interpret these.

  • Tables: Remember that you are listening to the Web now, not viewing it. Because the screen reader is very logical, the content of the table is read out loud, starting with row 1, column 1; then row 1, column 2; and so on. This can be very confusing to follow. Sometimes, tables are used not to represent organized data per se, but to make elements or text look pleasing onscreen. Imagine what that might sound like.

Although many more challenges are encountered using a screen reader to access Web pages and PDF files, these examples provide you with a glimpse into the world of listening to your computer.

PDF Files

Adobe's support of Section 508 has resulted in the compatibility of some screen readers with Acrobat 5.0. The ability to created tagged PDF files that work with screen readers enables no-vision people to listen to the content of those files.

If PDF files are not created with accessibility in mind, the contents of such files are not useful for those who listen to their computers with screen readers.

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