Section 508
Handicapped people may have Readers that help them understand websites. But in order for those to work well the website should meet certain standards. These standards are captured in Section 508.
The organization that manages it also has tools that can scan your website to see to what extend it is compliant, and what parts are not compliant. The teams work on these findings to improve the websites to become 508 compliant.
The tool is called Wave, which stands for “Web Accessibility Evaluation Tool”. It is a Chrome Extension that scans a web page and reports various errors and alerts. The company that provides this tool is WebAIM.
However, there are also consultancy companies that can do more extensive 508 compliancy checks.