I might add that this particular hunter (that is owned and shown by a good friend) has a Vet certificate stating that the horse is not unsafe and otherwise perfectly suitable to participate in hunter competitions. He has been doing so for years now so I am sure if there were some Equine Canada rules infraction it would have been caught be now.
I think, technically, it is considered an unsoundness. Like others have said whether you place or not will be up to the judge
I’m in Virginia and there is a very, very nice large pony locally that has won at the USEF “A” shows and is missing an eye. That pony is safe as they come and the judges pin it every time (as they should).
Not a pony but I have a barnmate whose Adult Hunter only has one eye and she shows him at rated shows without issue. He’s a great horse. Since being one-eyed is all he’s ever known, it doesn’t seem to affect him. I don’t think she’s ever felt that his eye has been marked against her. He was born with one normal eye and one that was super underdeveloped so it looks like not much is there but an empty socket.
He wears a prosthetic eye, not only to keep the socket clean but also for appearances. When he has his show eye in unless you are up close to him all it looks like is that he has a smaller pig eye on one side. His division doesn’t jog or model so a judge isn’t likely to be up close and personal with his eyes either.
My large pony had one blue eye and people used to come up to her at shows and start waving their hand in front of her while simultaneously asking “is she blind in that eye” – all the while my pony is freaking out like WHAT ARE YOU DOING HUMAN?