Assuming you've already wiped off and/or cleaned the lens, I'd suggest taking an extra close look at the camera itself to make sure the lens isn't cracked. I've had that happen on past vehicles, but the backup camera on the TB is neatly tucked away specifically to deter that from happening. That being said, if it is cracked, you'll have to either take it to the dealer or go old school and research the part numbers and such.
The 8" display is the HD version and should have a clear picture. You can add a picture here by selecting the picture icon (looks like mountains with the sun) and then add a picture from your phone. I also have the 8" display and my view is nice and clear.