Bloc-Loc Flying Geese template 2 1/2" by 4"made it easier to keep all the same size. I do hope the medical field will know more about the Optic nerve in the eyes someday. The left eye 'blew' out with no warnings and the right had some warnings signs that I immediately sought help for...so some vision saved there and I feel very blessed. If you close your eyes and see bright reds and blues, seek help quickly! Doctors. do not know what causes optic nerve to swell up or blow out in the back of the eye, by some miracles, they save a few.