Learning About Horses - Sight & Eyes

 Learning About Horses - 

👀Horse's Eyesight👀

As I was thinking about training Lilly and getting a flag to use with her I had a thought - what CAN horses see. I know that dogs can not see the same colors as humans so it made me think about what colors will Lilly be able to see. This lead me to the following discoveries. 

Scientist are still learning about horse vision. There is many contradicting facts out there in the world of horse vision. This is what I have found that seems to be the most accurate/uptodate information we have about horse vision. 

"Equine vision is different from human vision in almost every way---acuity, range, eye contact and detection of peripheral motion, just for starters." 
Acuity - humans have 20/20 vision. This means that you can see something 20 feet away. A horse's acuity is 20/30 (20/60 one study showed) which means that details we can see from 30 feet (60 feet) the horse can only see them if he is 20 feet away. The horse has to be 50% closer to see the same details. Horses can also be nearsighted or farsighted. Horse acuity also changes with age. The best acuity in horses occurs around 7 years old. Before that it is still developing. After that, it is declining. The size of the nose also factors into acuity. Long convex horses have better acuity than horse with short concave noses. 

Points of View

The horse sees 4x more area than we do. This means they are going to see things before we do and since they are prey animals more things are going to be threatening. The horse's vision is poor above and below his eyes. A horse can not see the person standing directly behind him so always approach the hindquarters from the shoulder.

A horse also can not see from his eye level to the ground below his nose. He can not see the grass, the bit, the fingers that stroke his muzzle - he uses his mouth & whiskers to sense these objects.

Visual field - this is the area that an animal can see.
Horses' eyes are positioned on the sides of head (laterally).

Range of vision is 350°
65° binocular vision (humans have 90° binocular vision)
285° monocular vision
The range of a horse's monocular vision, blind spots are in shaded areas

A horse has two blind spots = in front of the face 3-4 feet and right behind its head which extends over the back and behind the tail when standing with the head straight forward.
Horses have a smaller field of vision for depth perception than humans.

A horse can use binocular vision to focus on distant objects by raising its head.

A horse with the head held vertically will have binocular focus on objects near its feet

From what I am seeing it is really important to use loose reins when riding so the horse can see where is it going. Being able to move their head up and down so they can use their binocular vision is going to help the horse.
Horses are also more objective when it comes to what they are seeing. Human brains are more prone to illusions and assumptions.

Looking Sideways

Trying to make a horse look at something head-on is making the horse use their worst vision. The horse needs to look at something sideways in order to see something clearly. How to help a horse - if a horse is scared of something they see - allow the horse to more in circles or loops at the closest distance she considers safe. Use vicarious learning - let the horse see a familiar human (or even better another horse) walk to the object, stand next to it, and speak calmly. She will recognize the voice. Stroke her neck and encourage her to approach. A step or two more than she wants is success. Stop and come back at it another day. When the horse is relaxed at a distance ask her to walk back and forth past the object. Than if she is willing ask her to advance head-first and allow her to sniff the object. Stroke her neck and speak calmly. She will probably jump a few times. Touch the object to make it make a soft noise so she can learn more about the object by using her excellent hearing. Always listen to the horse. Do what the HORSE is comfortable with. You are able to see things differently than her. Remember that!

Predator and Prey

We are predators. Horses are prey. This is a biological fact. Our forward facing eyes tells our horses that we are predators. Prey animals identify predators by smell and sight. Human eye contact has a warning effect. Use it as a reprimand ONLY it is the human equivalent of an alpha mare's flattened ear. If a horse is moving too quickly slow down. Look down, watching and listening to her feet. If a horse is hard to catch - look to the side and slowly walk backward toward the horse while speaking quietly.
Horse MUST be highly aware of peripheral motion. It doesn't matter if they know WHAT they saw they just need to notice peripheral motion immediately so they can leave at a high speed before a potential predator begins to approach. 

The human brain takes half a second to process - this half second is out of the question for a horse in the wild. Every millisecond delay could mean death. Nothing is lost from running from a harmless object.

To help the horse - sharpen YOUR peripheral senses. Become MORE aware. If a horse is more nervous in an area he was not been nervous in - he notices something that you do not and is trying to tell you about it.

What People See	Why	What Horses See	Why
A large opened silver gate	Your eyes auto-focus using flexible disc-like lenses that are attached to powerful ciliary muscles. These muscles flex or relax as needed to adjust your lens shape so you can send a sharp image to your retina.	A hologram with a collage of silver arms, shimmering in and out of focus reaching forward as he approaches and passes it	They have eyes monocular vision because they have eyes on the sides of their heads. Their eyes work independently sending separate images to separate sides of their brain. Only when your horse has directed both eyes on an object can they see in binocular vision. The horse has much less flexible ciliary muscles. In order to help his eyes focus he must move his head, adjusting the distance between his eye and the gate.
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10 pound yellow cat sitting on a stump to the right of the driveway	Your eyes autofocus and instantly sends your retina a sharp image of the cat	A cat the size of a Cocker Spaniel	Horses have the largest orb found in a land mammal and has an oversized retina. This means that up-close objects look 50% larger than they appear to you
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You see a couple of white-tail deer 50 years below and to your left, grazing in front of some trees	As you get to the top of the hill, you turn your head slightly so that the deer remain directly in your binocular line of vision, as you turn your attention back to the driveway the deef fall into your peripheral vision and they become fuzzy clump of tan blobs	Depends on his position he may not notice the deer since they are slightly ahead and to the left of him at a lower level than his head. As he passes over the hilltop the deer enter his peripheral vision and become crisp, sharp images	He can't see them clearly from the hilltop because his eyes operate in a manner similar to bifocal glasses. Looking through the lower half of his eyes - as he would at the deer below - he can clearly see up-close objects but not those in the distance. Looking through the upper half of his eye he can clearly see distant objects but not those close up close "visual streak" a 215° area area horse's vision is the sharpest due to the density of nerve cells - superb peripheral vision. He is genetically programmed to pick up slight, invisible to you movements.These slight or invisible to the human eye are big-screen occurrences to your horse. If deer are quietly grazing the horse will not be worried about it. If the deer where to suddenly bolt into the woods the horse would spook (and you would not have seen anything)
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You see your German Shepherd trotting in from the field to join trail ride he zigzags "herding" your horse	Your forward facing eyes see the whole scene when you turn around - you are convinced your dog's herding is harmless and you turn around and face forward	The horse's right eye sees a pony-sized dog. The dog disappears and another pony sized dog appears in his left eye.	The horse's monocular vision makes his brain process the information separately. The dog is a new threat. Each eye sees the dog for the first time.
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Neighbor standing ahead at end of driveway wearing Panama hat, hot-pink hatband, brown and yellow striped shirt, unsightly bilious-green stretch pants	You see the world in lots of colors so your neighbor's fauz-paus leaps out at you - you wish you were color blind	Horse sees a large human with green legs, yellow and gray toned body brown/gray straw-looking thing on her head which may or may not be edible	Horses can perceive SOME colors. The most vivid color is yellow, followed by green, then blue. Brillant colors are not important to horses. His predators tend to be brown so red is seen as a brown/gray - a non color. Your horse is not frightened by bright colors. As long as the neighbor does not make any sudden movements he will quietly accept her presence.
____________________	____________________	____________________	____________________
Neighbor offers a piece of pie while motioning to a small, grassy paddock we can put the horse	Your eyes works as one and you can see each part - you untack your horse and turn him loose in the paddock and eat the pie	Horse sees grass immediately drops his head and digs in	Unless something catches the horse's eye he will munch away. While grazing, horse remains aware of his surroundings to detect potential threats by looking through the tops of his bifocal eyes. If he perceives anything he will raise his head and arch his nect so he can continue to use the top halfs of his eyes.
____________________	____________________	____________________	____________________
Dusk settling in, dimming your ability to discern shapes or see long distances	Your eyes are poorly designed for night vision because they lack the light absorbing/reflecting mechanisms to see clearly in dim light - you hurry to finish your pie, retack horse, and hurry home	Head back home images look brand new to each side of his brain - he can see clearly despite the lack of light	Due to low-light perceiving receptors in his eyes your horse's night vision is about 50% better than yours. He also has reflective panels on his retinas that catch small amount of light still available at night. He will probably stroll home with complete ease because he can see well at night and there are usually fewer activities. He will be less spooky UNLESS you are nervous which you can easily transmit to him.

Horse and Rider

Inside a horse's eye

Retinas

Most animals the retina is consistent, smooth, concave surface - the horse's eye is different. Its retina is more concave in some places than in other places. Some sections are nearer the cornea than others. Horses are dependent on the retina for good focus and clear vision. Horses CAN NOT focus its eyes like we do. Instead it makes sure of the irregular surface of the retina by lifting, lowering, and weaving its head. 

Ciliary Muscles

Ciliary muscles in humans and many other animals are strong to help facilitate lens adjustment - Horses have undeveloped and it does a poor job in helping the horse focus.

Pictures

It also sends two separate pictures at the same time with each eye. It would be like if a human was trying to watch two TVs at the same time. 

The eyeball is like bifocal glasses. While it is grazing it is looking through the upper portion of the eye and will lift its head to examine the object using the lower portion of its eye. 

Biggest Eyes

Horses have THE BIGGEST eyeballs found in ANY land mammal. This means they also have an oversized retina. That means objects are magnified. It is about 50% larger. A large dog might appear as a large as a small pony. 

The horse also needs to be trained with BOTH eyes. It must see the same things first with one eye and than with another eye. 

Horses and Color 

What does this mean? This means if you want a horse to see something really well - use YELLOW!!!! But DON'T wear or use yellow when training the horse. For example, don't wear yellow clothes or use yellow flags as this will be too startlingly for the horse. 

But research shows horses react more to yellow, white, black, and blue floors - so these are NOT good option for floors. “Adverse reactions of the domestic horse to environmental stimuli can be problematic in training and management. Hesitation and alarm reactions to visual features of the ground can occur in both ridden work and when handling horses.” It is better to have floors that are green, red, brown, or gray