I don't think schizophrenia has any dependence on visual input at all. This is just a probability problem, since the combined probability of both occurring is very small, as the separate probabilities are already small; Anyone that has a brain can have the disease, blind or not; The disease itself is very little understood. For example, when I was a child I had visions and heard voices. I would go to sleep and then, in the middle of the night I would wake up and start seeing things around me, hundreds of voices talking, light beings, etc. Some would call me a schizophrenic, some a medium. I could be both, could be neither;