What's "audio description" on tv?

It's an additional commentary that helps people with a sight problem to picture the on-screen action, body language and facial expressions.

Audio description and subtitling services are currently available on  Cartoon Network, Cartoon Network Too & Boomerang, which include shows such as Ben 10, Foster's Home.., Billy & Mandy, Codename: KND, Scooby-Doo and Dexter's Laboratory.