When you take the time to learn more about your horse’s vision, you will understand why some things spook him. You will also be able to communicate more effectively with him. In fact, a large part of our riding success depends on the horse’s ability to see the way we want him to move.
We have all heard that horses are colorblind or even that they see the world in black and white, but this isn’t quite true. Horses actually experience a full spectrum of colors, including blues and yellows, although they do not see vibrant colors like red and orange.
They have a wide field of vision, and their monocular (one eye at a time) vision is excellent, although they do have blind spots in front of them and behind them. They are able to overcome these blind spots by simply turning or lifting their head. In this way they can improve their depth perception.
While horses have a wide range of vision, they do not have the ability to focus close up like humans can. For example, a human can see details at 20 feet that a horse can only perceive at 30 feet. This is a major reason why riders must keep a loose rein and let the horse move his head to make sure he can get a good look at a fence or a person.
Because your horse is a prey animal, he has specialized receptors within his retinas that detect slight or invisible movements. These movements, which are big screen events for him, set off his survival instincts. The flutter of a bird’s wing, the movement of a shadow or a ripple on the water are all big-screen triggers for him.
This is why horses are so sensitive to a light touch on the hand, as the slightest pressure can cause a spooking response in him. It is also why it is important to teach your horse the feel of a touch on the hand and to use this as an indication of what you want him to do, rather than merely for control.
Horses can see very well at night, as they have a rectangular pupil that allows for decent sight and their tapetum lucidum – an internal structure that reflects light – helps them discern shapes. However, the clarity of their vision is reduced as the ambient light dims.
We have all seen a horse react to a sliver of sunlight on the ground as if it were a rattlesnake. This is because the sliver changes shape and direction as it moves across the ground, and your horse perceives these variations as a predator moving towards him. This is why you must be careful not to overdo it with groundwork exercises that require a horse to follow a small sliver of light. The horse is always on the lookout for a snake!