Sitting in a raft afloat the Eagle River, Roger Hill peers intently through his glasses as he struggles to tie on a fly. Now 84, he has wiry white hair and a calm voice buoyed by wry humor. He sits with his shoulders hunched, his blue eyes laser focused on the hook eye. The combined effects of glaucoma and essential tremors make it hard for him to thread a line through it. I want to lend a hand but don’t. For I, too, know the pride of self-su…