Yes it could be all of those. How old is your bird? What is his diet? Does he have a UV light? How do you know he can?t see? You need to find an avian veterinarian immediately.
You will have to Find an Avian Vet and take your bird to them for help as we cannot tell you anything about this over the internet nor can anyone else.
Your bird has to be checked out by only an Avian Vet to make sure he is diagnosed and treated correctly.
There is a link on site here for help in finding Avian Vet, and you can also talk to a breeder about who they use for their birds.
This is not necessarily age-related and could be related to poisoning instead, so you have to have bird examined by a licensed Avian Vet.