Understanding How Horses See

 There's no difference in the vision of these horses, although some people may feel they look more likely to spook. 

Natural Eye Protection

The protective layer in the corner of a horse’s eye, 

called the nictitating membrane, helps prevent irritation from dust and objects like grass seeds and stems. You'll often see a bit of tearing and grime in this area that can be wiped away with a soft damp sponge or cloth as part of your grooming routine.

Thinking that horses see the same way we do would be a mistake. It's important to understand how they perceive the world, why they react the way they do to shadows and changes in light, and the extent of their close-up and distance vision. When we're doing things like designing stables, loading horses on trailers, or riding out on trail, it helps to understand what those things look like from the horse's point of view.