R Yehudah holds that a blind person is patur from mitzvos; however, R Akiva Eiger (shu"t 169) qualifies this view and says that even R Yehudah agrees that a blind person is obligated to keep lavim. His proof: Tos (R"H 33) writes that a blind person can recite a bracha on mitzvos because even though according to R Yehudah a blind person is exempt mdoraysa from mitzvos, he still has a chiyuv mederraban to do them. The source for the obligation to keep dinim derabbanan (and the source for reciting brachos) is the lav of lo tasur, the lav of not disobeying beis din. If a blind person is exempt even from lavim, what would obligated him to keep a derabbanan? How can he recite vi'tzivanu on them? QED there is a chiyuv in lavim.
There seems to be a Yerushalmi against this view. The Yerushalmi (13a in vilna pages, end of second perek in sota) darshens from "vne'elan mei'euney isha" that the wife of a blind person does not drink sota water. The gemara then writes that this follows R Yehudah's view that a blind person is exempt from mitzvos.
What the Yerushalmi seems to be saying is that since the blind person is exempt from mitzvos, even issurim, there is no problem with him living with his potential sota wife (see Korban Ha'eidah. The Ohr Sameiach does not understand the Yerushalmi this way, but I don't understand what he is saying.)
So it could be that R Akiva Eiger's chidush is a machlokes Bavli and Yerushalmi. (Other Achronim take issue with the proof itself. As we've discussed before, there are reasons other thsn lo tasur that might obligate a person to keep dinim derabbanan.)