Hello, I am a random person here via Latest Things. I think it's likely that a lightbox could do some good for a completely blind person. I don't know of any research specifically on blind people, but I do know that light exposure can be effective when the light source is strapped to the back of (seeing) subjects' knees so that they can't really see the light. My guess is that you'd have to put the light quite close to your skin and leave it on for a fairly long time, but it might do some good for mood / sleep cycle related things.