Help for ESA Dog Rambo

Rambo is a neutered,up to date on shots ESA pup. He is 5 Years old. 2 days ago he suddenly lost vision in his right eye.  He WAS taken to the vet immediately and sadly they have no idea what is wrong, gave him 3 meds and suggested an opthomolgist. Within the last 18 hours he lost the vision in his left eye as well (after the vet visit). I am transporting him today to Wilson's Emergency Vet as something is very wrong. Please help if you can at all.