Horse eyes

The placement and structure of your horse’s eyes is vastly different from a human’s. While we can easily wear glasses to correct poor vision, this isn’t possible for horses.

Also, we are used to a clear field of vision in front of us. Horses, however, have amazing peripheral vision with two blind spots—one directly in front of its nose extending around four feet in front of it, and the other behind the tail, about ten feet long.

When you consider the front blind spot, the abilities of jumping horses seem all the more incredible. The horse loses sight of the obstacle when it is a few feet away and has to rely totally on the rider to tell it when to jump.
Horses also are unable to focus their eyes the way humans and most animals can. Have you ever seen a horse raising and lowering its head as it looks at an object? It does that to adjust the focal length, moving until the object comes into focus on its retina. Also, since the horse’s field of vision doesn’t overlap—the right eye sees what’s happening on the right side of its body, and the same on the left—it’s amazing that the horse isn’t confused all the time by two images that don’t match up at all.

The horse’s eyes also act something like a human’s bifocals. If the horse lowers its head and looks up, gazing through the upper portion of the eye, it can focus on the horizon. However, if it needs to look at something closer, it will raise its head to regard the object through the lower portion of the eye, where it can focus more clearly.

When you see a horse startled by a sudden movement just behind or beside it, its peripheral vision has sighted the movement but it has not yet had time to focus on it. Even when the horse is traveling a familiar path, such as to the stable or pasture, it can be startled by something as small as a paper blowing past.

Horses’ night vision is generally superior to that of humans. Horses have a reflective panel on the retina that helps to gather all available light at night. However, horses have a much lower sense of color than people. While they can distinguish green and blue, a horse’s sight is mostly in shades of gray.
Eye injuries and infections are common in horses. This is just one of the reasons you should check your horses—and not just from over the pasture fence—at least twice daily. Untreated eye problems can become very nasty very quickly. Minor problems can result in blindness if left unattended. If the eye becomes badly infected, the structures of the eye can be eroded until the entire eye collapses. But with prompt treatment many eye problems can be brought under control within a few days.

Your horse’s eyes should be clear, bright, and the lids tight, with the inside of the lid pale pink and moist. Tearing should be minimal with perhaps only a droplet at the corner of the eye. Image #1 shows a healthy horse's eye.

Treatment is necessary if:

* An eyelid is cut or torn.

* The lids are swollen.

* Obvious damage to the eye itself.

* There is a white film—either over the whole eye or in spots.

* The eye or any surrounding tissue including sclera and lids appears red and inflamed.

* There are tears running down the horse’s face which may indicate a torn tear duct.

* Any other copious discharge.

* There are tumours growing on the lid.

* In foals, turned under eyelids that cause the eyelashes to rub against the eye.

Image #2 shows a horse's eye that needs treatment.

First Aid for Eye Injuries and Infections

If your horse has an eye injury or infection:

* Clean up the area very gently with a saline solution. If you don't have one on hand (like the saline solution for contact lens wearers) you can make some yourself. The ratio is about 1/4 tsp of table salt to a cup of lukewarm water. It should taste like tears.

* Put a fly mask on the horse to keep flies off the eye area.

* If possible keep your horse in subdued light such as his stall until the veterinarian arrives.
How the Veterinarian May Help

Rips and tears in the horse’s eyelids should be attended to by a veterinarian so the lid can stitched if necessary. The vet will also check for damage to the lens and anything that may be lodged in the eye (splinters, awns from grasses or grit).

The veterinarian will probably give you an ointment or gel to apply to the eye. In some cases he may draw a vial of the horse’s blood and make a solution from it that you will irrigate the eye with. With all medications make sure that you follow the veterinarian's instructions to the letter and be scrupulously clean as you apply any dressings or ointments.

How You Can Help Your Horse Heal
Just because you see marked improvement quickly, don’t stop medication until the full course is up. Stopping treatment before the infection or injury is completely healed can result in the infection flaring up again.

When working with a horse with an eye problem be aware that he may have obscured vision and be a little more spooky than usual. Talk gently so you don’t surprise him if you walk up on a ‘blind side’.
Preventing Eye Injuries
Your horse’s environment should be as dust free as possible. Make sure that sharp edges on water troughs, metal buildings, pipes or other obstacles are covered or inaccessible. Pound in or pull any old nails that may be protruding from fences or other structures.

Many injuries are caused when horses are playing or scrapping and this is almost unavoidable. Just take care to make your horse’s home as safe as possible.