Designers often use tables to achieve a certain layout on a page. For example, tables are commonly used to connect multiple small images to form the look of a complex, odd-shaped image. Tables are also commonly used to wrap text around images or to provide a sidebar of navigational links on the page. While the visual effect of these pages is often very appealing, it can cause problems for disabled computer users accessing the page. Many visually impaired individuals use screen readers to access web pages.
Screen readers are programs that audibly read the text on the screen.
When tables are encountered, the screen reader linearizes the table. This means that it first reads the text in the first column of row one, then the second column, then the third and so on until all columns in that row have been read. It then reads all columns in the second row then the third and so on. This is because designers rarely organize their content in logical rows and columns. Although sighted users can understand the content, it can be very confusing to users with visual impairments.