Thanks for taking a close look at the close-up pics. I haven't had another look at the squirrel or his eye. He doesn't show any sign of wanting to come out of his nest box when I'm in the room.
Good news! Day 7 yesterday and he is finally moving around when he comes out of his nest box. It has taken a whole week!
He came out of the nest box 8 times yesterday, vs the 2-3 times previous days. His movements are slow, but he climbs up the tree limb and can cling while eating the peanut butter. He loses his footing when he climbs down, but hasn't fallen. He has peered out of the cage for the first time. So hooray, it seems like he's "waking up."
Squirrel watcher in Alaska.