i actualy think its not required.
drop eye doesnt kill the fish, putting it in such trauma so it looks nicer is wrong i think. like cropping ears of a dog.
fanning the tail is rather disturbing, once again like cropping ears of a dog.
i dont like it how in asia, so many things iwth animals are rather cruel. like the sweet heart parrots, amputating tail over and over again so someone can have a retarded looking fish. it really isnt right lol
in philippines where i am from this is a common thing..... personally i would never risk my fish like that.... jsut so one eye looks more upward than downward.
i have a 1.5 red aro, one eye had drop eye from its old owner putting it in a bright room with no covers on the side etc. always freaked out
when i got it, size doubled in less than 5 months. with good care..... it still hunts food, as well as any other aro i have ever seen
i reckon drop eye isnt a disease.
i reckon drop eye is an adaption that aros get.
in the wild, silvers also have drop eye
perhaps food doesnt always come from above, so they probably get drop eye to enable them to more effectively hunt below.
just a thought