Cliff, I don't know specifics but if you go to the attached website, I believe that some of the information might help you. It is from the BEBRF Main Pages on disabilities. Towards the bottom of the listings, it talks about legal aspects. See if you can find some information, there.
Someone else on the board might be able to help you more specifically. I believe that the answer is yes to your question and that they do have to provide accommodations. Sorry, that I can't be of more help. http://www.blepharospasm.org/disability.html
Shirley in AR.