How good is a horses' vision?

Horses have both incredible vision and limited vision:

Because horses have always been "the hunted" and not "the hunter", the prey and not a predator, their wide set eyes positioned on each side of their head are designed for a very wide range of vision that can tune in to the slightest flutter of movement across long distances. This is a necessary ability in order to avoid predators such as wolves, coyotes or cougars. No one is certain how far away a horse can see but it has been estimated at approximately a quarter of a mile!

Around their body, the horses field of vision is almost 360 degrees. Their two blind spots are directly in front of them (about 10 degrees) and directly behind them (about 10 degrees).

Those soft, curious eyes are twice as big as ours and what's even more amazing is that their eyes are larger than the eyes of both whales and elephants! They have one of the largest eyes in the animal kingdom. A layer in the eye called the tapetum lucidum greatly intensifies light and reflects that light back on to their retina, which make horses well equipped to see in the dark, much like a nocturnal animal. (It's also why a horses' eyes get that eerie green glow if you shine a flashlight towards them in the dark). To appreciate their night vision, consider this: when the electricity goes out, you and I may slowly grope and feel our way through the blackness of our house that we're very familiar with (and still do a flying squirrel maneuver over the coffee table!), while a horse can run a winding trail at night, weaving its way through trees with little to no difficulty.

This ability to see long and wide also causes some limitations. They don't see objects up close very well, especially right under their muzzle. That's why you'll see a horse often bump their nose and get startled at something (because they didn't know it was there!) or nip, nudge and feel around for your hand when you offer them a treat because they can't see it.

The wide set eyes also mean that the horse doesn't see details up close or have the depth perception that you and I are accustomed to. Things they see appear to be flat. To get a good idea of what this is like, cover one of your eyes with a hand and then try walking or running. It will give you a whole new appreciation for the horses various athletic abilities!

While facing forward, a horses vision is best from about 6 feet away and beyond. In jumping events the rider is putting a lot of faith in the horse and vice versa: the horse is really putting a lot of faith into their rider because the closer a horse gets, they can't actually see the jump! If they see it at all, it is not clear. They are basically jumping blind. How much more we should respect these magnificent animals for their willingness to do something so dangerous and uncertain, just to please us.

Can colic cause blindness?

Colic itself would not normally cause blindness but certain types of poisons can cause colic and blindness.

One of the most common poisonings in horses is called moldy corn poisoning. It happens most often between late fall and early spring, after corn has been stored that has too much moisture in it, or has been stored in an already damp area, which makes the corn moldy. Moldy corn will be discolored with shades of pink and/or red to reddish-brown colors in it.

Moldy corn poisoning causes what is known as the blind staggers. A horse that has eaten moldy corn will exhibit signs such as circling and staggering, doesn't blink when you wave your hand in front of their eyes, confusion and will panic for no apparent reason. A horse can die from moldy corn poisoning in just a day or two once these signs begin HOWEVER it IS possible save them if the signs are detected and a vet is called soon enough. (Of course, get the corn away from the horse or get the horse away from the corn immediately!)

If you suspect that your horse has eaten moldy corn, don't delay, call your vet!