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Understanding How Screen Readers Work [Video]

If you’ve been reading through the Accessible PDF series, you might be feeling a little exasperated with some of the extra steps required to create a PDF. To keep you from throwing up your hands and saying “Really, Jayna? Isn’t this a bit much?” I thought it might be helpful if I explained a little bit about screen readers and the people who use them. So let’s jump right in.

What is Assistive Technology?

Assistive technology refers to assistive, adaptive and rehabilitative devices for people with disabilities. This technology allows users to perform tasks by creating alternative ways to interact with content.

When paired with a computer, assistive technology can include screen readers, screen magnifiers, alternative keyboards, braille embossers, assistive listening devices and various mobility enhancing devices. 

Who Uses Screen Readers?

People with visual impairments use screen readers, as well as people with learning disabilities such as dyslexia and ADHD. A screen reader can help users cut down on the “visual noise” on a page and focus specifically on the content.

How Does a Screen Reader Navigate?

Just as sighted people scan the contents of a web page to find what they are looking for, a screen reader gives users the same capability. Screen readers can navigate a page based on heading structure and link text. 

Screen readers use a variety of keyboard commands to carry out tasks such as scanning the contents of a web page, reading documents, and opening and closing files. The size, style and color of the text can also be conveyed to the user, but those settings are typically not on by default. That’s why it’s key to use appropriate underlying code if you are using text styles that are important to understanding your information.

What’s the Big Deal with Hyperlinks?

Screen readers read the link text associated with each hyperlink. This means that if you’ve just included a url as a hyperlink in your document, the screen reader will spell out every letter of that url, which can create user fatigue. Also, because users can navigate a page using hyperlink text, it is important to use descriptive link text that can be read out of context. For instance, avoid language like “Click here” and “Read more” and instead provide a better description of where that link leads.

Why Do My Images Matter for Screen Readers?

A screen reader detects that an image is included with your content, but if you have failed to provide alt-text, it will only read the file name, which in many instances is just a number or a half word that has no meaning. 

If your image conveys information that is important to understanding your content, you need to provide alt-text, which is a description of your content. If you frequently use images or other visual content with your course content, I encourage you to read this alternative text article from WebAIM. It does a great job of explaining how to write good alt-text.

Why Can’t I Create Complex Tables?

Screen readers makes sense of information in a linear way. They read tables from top to bottom, left to right. Some screen readers will repeat the row and column headers as users navigate the table.

Using merged or split cells in your tables confuses the reading order and can make your information difficult to follow. Instead, consider breaking down your information into multiple simple tables (with no merged or split cells) or rethink how you are presenting the information.

To learn more about tables for accessibility, refer to these resources:

Jayna Phinney
Jayna Phinney

Jayna Phinney is the Instructional Technology Specialist for the ASU College of Science and Engineering. Contact her at or 325-486-6264.



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