the scaling over the eyes does hamper their vision a bit, yes. if you could get pictures to show what you mean exactly, it'd be easie to tell you. x:
but, that IS a HUGE problem in dragon bettas. many times, breeders aren't careful about how they breed them, and the scaling covers the eyes and causes the bettas to be either totally blind, or partly blind. the best way to keep this from happening, is to watch the bettas you want to breed closely. my brother's dragon didn't go blind until he was at least 2 years old(roughly. he was a pet store betta), but then there's some who show blindness almost right away.