Published: May 19, 2016

The purpose of the Digital Accessibility Office (DAO) is to make sure web resources are accessible to blind and low vision people at CU Boulder. Since most blind and low vision users access computers and mobile devices with either screen reader or magnifier software, it can be helpful to understand what these technologies are.

Screen Reader Software

A blind person accesses a computer by using software that verbalizes what the computer is doing.  A user can learn information about the content on the screen, possible actions, and changes as they take place. Here is a demonstration of someone using a screen reader. A screen reader uses a variety of strategies to convert the content that appears on the screen into a version that can be read as text. Because the content a user needs to interact with is always changing, the strategies the software uses are also changing. As a developer, it is not necessary to understand exactly how any of the assistive technologies works, but it is important to follow guidelines that make it much more likely the final product will be accessible. One way to do this is to use the WCAG 2.1 Standards for Web-Based Content. While they are not perfect, they are fairly comprehensive.  It is also important to have native users test a web-site or application. We do this testing in the AUL, and also have resources for other people who do it.

Some of the more common screen readers are Microsoft Narrator, JAWS, Window Eyes, and NVDA on the Windows platform, and VoiceOver on the Mac OS X platform. There are other technologies designed more for users with reading challenges who can see the screen,  but these are different from screen reading software.

Refreshable Braille Display

Some blind users also use a refreshable braille display, which is a flat, rectangular device with pins that rise and fall to form braille characters.  A user can obtain all the same information they would audibly.

Screen Magnifier Software

A person with low vision might use a combination of software depending on how their vision changes in different conditions, but a screen magnifier is one tool they are likely to use at least some of the time. The magnification software enlarges part of the screen based on where the user is focused, along with the cursor.  Some of the more common magnification software includes ZoomText, Virtual Magnifying Glass, MAGic, and a built in application called Magnifier on the Windows platform. There is also a built in screen magnifier feature on the OS X platform.

There are a number of features that might be important to a magnifier user, including smooth tracking as they move around the screen, the focus moving automatically based on new content appearing, color inversion, particularly to white text on black background, interpolation to smooth pixilation that can come with enlargement, and cursor customization so a user can circle the cursor or turn it into cross hairs to help with finding it.

Final Thoughts

  • A low vision or blind user is likely to have chosen a platform to conduct most of their computing based on a number of factors, but the accessibility tools available is likely to be a significant one. It is important to recognize that if asking someone to use a different platform, the learning curve to become accustomed to a new platform is likely to be higher.
  • In addition, there are tools for other platforms such as Google and Linux, but there is a smaller group of people using them, so they are not listed here.
  • This software is not the same as software where a user speaks information into the computer to have it complete tasks; that is speech to text software, whereas a screen reader is text to speech/braille software.