Vision assistance

Our goal is to make the information on available to everyone, even if your vision is impaired. Whether you are blind or color blind or whether you are in need of enlarged text or high contrast layouts, we strive to give you the tools to access information on

Screen readers

Many people who are blind access sites using a screen reader. We have worked to make this site as easy as possible to access with a screen reader.

It is possible to navigate through this site using only a keyboard. You can:

  • tab through the links on each page
  • jump to the content, local navigation, or global navigation sections on each page
  • use access keys to jump to specific pages
  • cycle through the headings on each page

You can learn more about how to do so on our keyboard navigation page.

Each page has been designed to be read in a sensible order for screen readers: first comes a few useful links, followed by the main content of each page, followed by related information and local navigation, then the page footer and finally the extensive global navigation.

Alternative text has also been specified for images, especially where images have a meaningful relationship to the content of the page. Titles have also been specified for many links if the text of the link might not immediately explain the destination of the link.

If you do experience any problems using this site with a screen reader, please let us know. We will be more than happy to continue to make improvements to this site based on your feedback.

Enlarging text

You may be able to see the site, but could use some help enlarging the text on the page to make it easier to read. This site has been designed to not only allow text to be resized, but for the entire layout to be resized to accommodate that larger text size.

Different browsers have different methods of changing the size of the text on the page. For many browsers like Firefox and Netscape, holding down the Ctrl- or Command- key and then pressing + or - will allow you to increase (Ctrl/Cmd +) or decrease (Ctrl/Cmd -) the size of the text. In Internet Explorer for Windows, you can go to the View menu in the top toolbar, go down to text size, and then choose Larger or Largest. Your browser may have different ways of changing text size, so make sure to check your browser’s help menu for assistance if these methods do not work.

Please note that if you do increase the size of the text substantially, you may need to scroll horizontally to see the entire page. If this is a concern for you, please let us know.

Color blindness and high-contrast viewing

We have done testing of this site to make sure that it is viewable for users with color blindness. While we have tried to provide good contrast in the text, we do not yet have a high-contrast version of this site available: this is something we will be looking at in the future. If either of these issues are a concern to you, please let us know.