aminoguanidine

It is known now that the optical nerve on glaucoma patients is due to the different changes in the eyes between pressure and less or non pressure. So the drops we are taking are reducing the pressure but are not protecting the optical nerve although I read that Brimonidine drops do a better job in doing so.  I found  out that aminoguanidine has been scientifically proven to protect the optical nerve in animal.  Can't find any research on humans.