if your aro is silver most likely that its the genes, because of the silvers are farm breed, its in their gene pool to cause drop eye, putting your aro into a pond will help but its it will totally cure it, as long as its healthy give tlc
I've come to belive it is not genetic , but caused buy your tank's shape .. most arowana keeper's have there's in shallow but long tank's like for example a 20gal long (only good for grow out at a small size).. tall tank's they say cause the aro to stare downword and cause the eye's to become asfixiated that way.This does'nt mean they can't see normal, it's like a person with a lazy eye..most of how'er asian brother's feed there arow's live and you don't see this condition in there fish ,so live food IMO is not the problem..
this is only my opinion, not a fact....but I say either get a wild caught silver or an aussie aro. The wild caughts i've seen dont have drop eye, but there is always an exception to the rule.
I adhere strongly to the theory of genetics, because IMO if it was any of the other things, we would see it as commonly in other aros as we do in silvers.