If you loose vision an eye while you're defending yourself, you're going to be disoriented and confused as hell whether you've practiced or not. I know; I lost most vision in one eye some years ago and it took a year or two to adjust. But if you've practiced one-eyed shooting, you're probably going to be better off than if you didn't. So I think it's a good idea.
For me, of course, there is nothing else to practice.
