CAPTCHA Treats Visually Impaired Like Robots


Sarah Norman is the new media intern for the Fall/Winter 09-10 year!  She will be blogging, tweeting and managing content for all of our social media outlets. If you are interested in guest blogging or have information on assistive technology to share, email Sarah at

Signing up for an account on Facebook or leaving a comment on someone’s blog may seem simple enough, but for the blind or visually impaired, CAPTCHAs can present a problem.  A CAPTCHA, which stands for Completely Automated Public Turing Test To Tell Computers and Humans Apart, is a device many social networking sites utilize to prevent spam and other harmful “bots” from entering.  In short, CAPTCHAs are tests that are meant only for humans to pass.  A typical CAPTCHA will ask the user to look at an image that contains distorted text and type the letters and/or numbers they see.  A blind operator would not be able to do this because screen readers cannot decipher the text in these images.

CAPTCHA with audio option, picture provided by Steven Vance on flickr
CAPTCHA with audio option, image credited to Steven Vance on flickr

More recently, popular websites provide an audio option for the CAPTCHAs.  Unfortunately, the audio version of a CAPTCHA is often so distorted that navigators can hardly make heads or tails of it!  I myself tested one of the audio CAPTCHAs, and after listening to it twice I still didn’t enter the correct text.  (Example of audio CAPTCHA)  I can only imagine how frustrating this would be for someone who is visually impaired.

There is hope.  New versions of CAPTCHAs are being developed at Towson University, a project they call HIPPU (Human Interaction Proof Universally Usable).  Instead of trying to read distorted text, users are asked to identify the object in an image or by the sound it makes.  For example, you might be given a picture of a car or a sound clip of a horn honking.  The leaders of this project claim that HIPPUs will be even more secure than CAPTCHAs because bots have a harder time recognizing graphics and sounds than text.  You can read more about HIPPUs here.

With any luck, more websites will realize that CAPTCHAs are shutting out a great deal of their audience, and should seek alternatives like HIPPU.  It’s important that these sites understand that while a visually impaired person could ask someone to help them type in a CAPTCHA, it limits their independence and treats them like spam.