Understanding how a horse sees the world can help a great deal when we’d like to know why horses act the way they do.Horses perceive their environment differently than humans because of the way their eyes are structured.
There is some controversy surrounding the eyes structure of horses. Horses were thought to have ramped retinas, meaning their eyes don’t form a true arc making the retina closer to the lens, but now it is believed that this may not be the case. A horse’s eyesight is optimised for grazing and watching for predators at the same time, but as such, it becomes a handicap when judging distance and height and this is why you’ll notice that horses lower their heads when approaching a jump. On approaching a jump, you may notice that horses lower their heads then raise them in an effort to appraise the height of the obstacle. When approaching an obstacle, the horse will lose sight of the jump right before takeoff; experienced riders take this into account and allow their horses to raise their heads before jumping.
As horses are color blind they can’t see colors as we do, they see the world as a mosaic of varying light reflections. They do however notice movement instantly and can react accordingly, much to the dismay of the inexperienced rider! An inexperienced horse may shy violently at any sudden movement, especially when in an unfamiliar situation. If something moves suddenly into their peripheral field of vision this will usually cause horses to bolt.
Horses, with their wide field of vision, have only two blind spots: that which is directly in front or behind them. When approaching a horse from the rear you should talk to him to avoid startling him. When tackling difficult terrain it’s a good idea to allow your horse free rein to enable him to find his footing easily.
Your horse’s eyes are very sensitive to light and this is why young or inexperienced horses seem nervous when you are trying to load them into a horsebox. Horses need time for their eyes to adjust to a darker environment such as a horsebox. Entering a horsebox is akin to entering a dark cave and your horse’s reluctance to do so is what saved its ancestors – caves housed dangerous predators!
Understanding your horse’s vision can help you understand why your horse reacts in various situations; a lot of the time inexperienced horse owners mistakenly believe their horse is intentionally acting up when the real reason for their horse’s behaviour is related to the his vision and way of seeing the world.