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  Discussion on Eyesight In Horses
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Posted on Tuesday, Apr 20, 1999 - 10:05 pm:

The question about foal cataracts has been moved to the Disease/Eye/Forum.

Hell Michael and Marlane,
One of the most notable features of equine vision is the horse is myoptic, short sighted, they can focus on that blade of grass but that blur in the distance... We all know they are very sensitive to movement however, it may be a blur but they know if it is a moving blur.

This bigger smaller stuff I do not know about. These are relative terms that are involved with the brain and learning through experience when we are first born. Consider this scene: a horse sees a human next to a horse, obviously the relative sizes are correct. Now do this thought experiment. Take the horse and the human and move them closer and closer until the observed horse merges with the observing horse, at what point does the human jump to a larger size?
DrO

Posted on Wednesday, May 5, 1999 - 9:39 pm:

HI Michael, from another Aussie :-)

Ok I have done a lot a tests and observations with horses and their eyesight.


Horses weigh us up as a physical threat, they don't consider our size in relation to them but more wether we push hard move faster or are more aggressive. I have now got a pinto that used to run over the top of me to close her eyes and squeal while she skids to a stop. This is due to fact that I crash tackled her head on when she tried to run me down. I don't have to touch her now she knows I can stop her so she avoids the issue. She see's me as the size I am, smaller then her but it is my bite she is worried about.
This is much the way Mob order works if you look like you will win then you are bigger than me.

As for eyesight, from my tests, I know they can see in colour, a slightly altered spectrum than ours. They can see full colour with a yellowish tint, but the main thing is their view of the world is overexposed to what we would normally see, I suppose this allows them to see into shadows somewhat. It also causes problems at dusk as the shadows and normal areas have the same light they get really night blinded.

As for binocular vision, it is only used as peripheral vision, the same way we notice things going on around us without having to look at them. But their brains can only process one image at a time. By image, this means looking at an object and deciding wether it is friend or foe. If two people approach a horse one from either side the horse will usually swing its head back and forth to look at each person in turn. Even though they will see either one move, it is only a reflex not a processed image.

Imagine you were driving a car, you are aware of the cars around you and the pedestrians on the street, If you saw someone you thought you recognised you would "look" at them and process the clothes they were wearing, facial feature, hair style. You could even do this without turning you head, this would mean you were using both eyes to view to world but only one eye can look at the target you have chosen. Horses work the same way they know what is around them but they have to focus on an object to "look" at it. Which means they have they see the same way we do but with wider peripheral vision.

Try looking at something a little right of centre in front of you then put a piece of cardboard or your hand sticking out from your nose, your left eye cannot see the object but you brain wont care.

The second eye is used to give you 3D distance vision, A horse can determine how far away something is by using both eyes and looking with its nose pointed at the target. As for distance clarity. I have been spotted at 1/2 km by brumbies and the Matriarch knew I was there and what I was and I sneaked into view so I was not a moving target. I know my horse can spot half a carrot in my hand a 200m.

I have also noticed that horses bob their heads up and down, to look at something a long way away, this is consistant with real long distance vision as the head moving allows them to determine the objects that are closer to the horse than the target.
It is great fun playing with brumbies as they are living on their skills, though they still are very curious. A few friends of mine was crashing through dense bush making a lot of noise, they thought they heard something, one of them talked, and suddenly the bush erputed with horses. The brumbies were not worried about the bush making noise, but for a man to talk, that was bad news and they left. They got within about 10m of these wild horses.

I also beleive horses suffer from many of the maladies humans do, The Pinto we are sure is colour blind, she can not see red on green even in front of her nose. All the others can.
some people say horse can see greens real well but reds are grey, if this were true horses would not appear to be colour blind the same as humans :-)

Posted on Sunday, Jun 6, 1999 - 2:38 pm:

I had a young WB gelding started under saddle last fall. He was at the same facility for several months, and would not get over being frightened by the small metal grandstand at one side of the arena. The trainer would tie him by it for hours at a time, but every day, he would react as if he had not seen it before. I've been told some warmbloods are very slow to mature so we brought him home, but will be ready to start up again this summer. He is 4 now. Are some horses slow to process information, same as people? could it be an eyesight problem?

Posted on Monday, Jun 7, 1999 - 7:14 am:

The specificness of the problem highly suggests behavior and has nothing to do with how fast he processes information.
DrO

Posted on Wednesday, Jul 21, 1999 - 8:50 pm:

It seems to be a common misconception that horses cant see very well or can only see motion.

They can see extremely well, even at very long range.

To us a horses vision would be like looking through opera glasses, magnified, and a slightly flatened view.

The only thing horses have trouble with if focus speed, but they seem to have very good definition and colour response.

I did a test a while ago with the Pinto we have here, I kept walking up to the fence from the house and wathcing her for a while, she got bored quickly and just ate the grass, about 50 feet from me.
I then grabbed a handful of hay, and stood at the fence again. With or without the hay I always kept my hands behind my back. This time even at 50 feet she noticed 1 single stalk of hay just visible behind my back.
She watched me intently to see wether I was going to give it too her, Then she ran up to me for it.

This Pinto has the worst eye sight of all our horses, and even she has better vision than me.

Horses don't seem to use there eyesight for finding good grass, at short range they tend to use their nose more.

Vetinary science seems to be slowly recognising the way a horse see's. They now recognise that horses see most if not all colours. I saw a comment recently that part of the horses eye, is used to amplify light, so they can see into shadows.

Posted on Thursday, Jul 22, 1999 - 11:27 pm:

I will have to dispute that horses can sense electrical current, otherwise my horses would not use their teeth to see wether the electric fence is on or not. Or that they would use their rugs as an insulator so they can lean on the electric fence.

But I will say that horses can definately hear an electric fence before we can. A fault insulator will put out a high pitched whine. A leaf or water near the current will make a small ticking noise (my horses get real uptight when they hear the fence tick).

Also with some experiments in electronics you can make head phones out of steel wool pads, if you put enough volts through them. So it is more than likely that there is an audible passage of voltage if you have a big enough energiser.

As to the other senses horse have, I will let you know when I can prove my experiments :-)

Posted on Saturday, Sep 22, 2001 - 2:39 am:

horses can see well at night or not so

Posted on Saturday, Sep 22, 2001 - 11:32 am:

I don't think its a see better, but differently. When I ride brandy at night (which took a lot of getting used to) she is calmer, less jumpy, more apt to soak in the environment. Like she is using all her senses more intensely. Loose pigs at night in the brush are no big deal. Loose pigs in the day in the brush are a BIG DEAL. LOL

I have much more sedate night rides than day rides. I always wondered about that. I took it as she turned on things and turned off things in her brain and therefore acted different.

I know that many things like cars coming at us at night and different sounds that might spook her in the day are less apt to spook her at night, probably since she can't see it moving.

This is just a personal observation i have no idea if they can see better or not, though.

jojo
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