John Brinkman, a development manager at Adobe, has written a Design Macro for checking the accessibility of PDF forms.
“One of the great things about PDF forms is that they have a really good accessibility story,” says Brinkman on Adobe’s FormFeed blog. “You can create PDFs and PDF forms that allow the visually impaired user to interact with the document with the help of a screen reader. However, the quality of the experience is entirely in the hands of the PDF author. If your PDF consists of only a scanned page, the accessibility story is very poor. If your PDF form is richly annotated with audible cues, then the accessibility experience should be very good.”
“The problem is that your average form author does not test their result with a screen reader,” adds Brinkman. “They may understand the guidelines to make a form accessible, but they do not get feedback as to whether the guidelines have been followed correctly.”
The program checks fields without captions, fields with no assist text, images with no alternate text, tables with no header row, and read order and tab order diverge.
For more on the macro, read this. A zip file is provided.