Horses are prey animals, so their eyes are located on the sides of their heads to give them a wide field of vision. This allows them to easily spot predators that may be approaching from the side.
Scanning the Horizon
Horses have excellent eyesight, and they use their large eyes to scan the horizon for predators, other horses, and potential food sources.
Communication
Horses also use their eyes to communicate with each other. They may use their eyes to show fear, anger, or submission, and they may also use their eyes to display affection or playfulness.
Vision in Low Light
Horses have a special layer of tissue behind their retinas called the tapetum lucidum. This layer of tissue reflects light back into the eye, which enhances their vision in low light conditions. This is especially important for horses because they are most active at dawn and dusk.