She should have gotten back on the horse right away, but that obviously can't happen now. I'd say let her hang around the barn, making friends with all the horses and develop a real closeness with them. Helping to take care of them, like grooming them, mucking out their stalls, making sure they always have access to fresh water, and bringing them in from the field if they're on pasture board ill help her and help the stable owner, as well. I'm sure her fear would disappear pretty quick.
BTW, because her other pony is blind in one eye is not usually a reason to quit riding it once it's become accustomed to its new situation, 'specially with a calm horse/pony.
One man's opinion, but something to consider.
Good luck, whatever you decide.