The vet came to see Blackjack, and determined that he had in fact scratched his cornea. But the scratch this time is fairly small and should heal quickly. He gets a 500lb. dose of Banamine once a day for five days, and two types of eye antibiotics twice a day until the vet comes to check on him next Tuesday. His eye is already looking much better - there's no swelling and the eye is fully open and not goopy, and he isn't uncomfortable.
Noble started on his thyroid medicine a few days ago, and it's too early to tell if it's helping, but I'm keeping my fingers crossed!
Enjoy your December day, and may it include horses!