Why do most mounts have severe cataracts?

[Pantz]

I doubt it. Who'd want to ride a blind horse? Before you know it you're off the cliff!

That's just where the fun begins ;D

Won't happen. You would run into an invisible wall.

[Felis]

Won't happen. You would run into an invisible wall.

Not every cliffs have invisible wall. As example you can fall down the cliff outside of camp dragonhead.
Only the cliffs with no way to go back have invisible walls.

[Jamesy]

Jamesy is here to lay down some facts. First a horse and their rider is a form of symbiosis as well most horses can't see directly below their jaw and a few have blinders. This is where horse riding becomes about trust specially with hurtles. The horse doesn't jump by itself most cases a que is given that being said if your horse ran off a cliff it would be the riders fault for not directing it properly.