Of course you won't go blind, you're not alive, dead people don't go blind. Think about it, vision decreasing is a process of aging, last time i checked corpses don't age. If anything it would probably result in the same thing that happens when an edo's limb gets blown off or something, the vision in the eye would restore itself just like the arms and legs do. Remember that an edo tensei body is in a state of animation whilst under that jutsu, meaning they stay animated the way they were when they died, that's why the technique is called 'Reanimation'