The eyes have it
Horses have some of the largest eyes of any land mammal (the moose takes the trophy), with a diameter of about 2 inches. Like many prey species, horses' eyes are located on the side of their head so they have a wide range of vision — they can see nearly 360 degrees, and have blind spots only immediately in front and immediately behind their bodies.
Horses mostly use monocular vision, meaning both eyes are used separately. So a horse can see and process different things happening on different sides of her body.
However, a horse also uses binocular vision when looking ahead, so she can focus both eyes on a single object in front of her. A horse will raise her head to increase her field of binocular vision and get a better focus on things in the distance.
A horse can't use monocular vision and binocular vision at the same time, but rather switches the type of vision she is using by changing the position of her head to face the object.
Horses can do a lot with their eyes. But there's something they can't do with their gut. Continue to the next slide to find out what!