Yay Hank! I knew he would be okay. Cole....I think Etamy Beth Halami (famous horse trainer, "cowboy dressage" was his thing) used a morgan stud that was totally blind for years...until Etamy felt the horse should be retired!
I know people with Appaloosas, who(the appaloosas) are prone to a type of blindness called "moon blindness", who use their mostly blind horses for dressage, reining, and gaming. It's about a total partnership, and total trust...If you have that with Hank, I would say...after some adjustment, don't worry!
Yay again, for Hank is a gentleman!