Equine Vision Explained

National Mounted Police Services Copyright © 2018
WHY HORSES SPOOK
It’s about perception

THE REASONING BEHIND THE
EQUINE FLIGHT INSTINCT
Understanding the Fundamentals of the
Thought, Learning and Vision Process of the
Horse

• States of mind regarding the learning process
• Equine priorities are a near constant
• Equine vision is dissimilar to human vision
• The thought process is not like humans
• Fight or flight, revisited

It is generally agreed upon there are only three
states of mind (with minor variations) to a horse
that affect not only his ability to learn but his
behavior as well
1. Relaxed state
2. Alerted state
3. Survival state

Equine priorities are a near constant
• #1: Am I safe?
• #2: Do I need food?
• #3: Where is the herd?
• #4: Can I rest?

Horses have
Monocular Vision
Each eye sees
independently of
the other eye
Each eye sees
independently of the
other eye
Equine vision is very dissimilar to human vision

When a horse looks forward, each eye sees individually and although
has approximately 90 degrees of “crossover” it does not give the horse
binocular vision due to the OPTIC CHIASMA operating at only 5% of
the human chiasma
National Mounted Police Services
Copyright © 2018

Monocular vision seriously affects depth
perception as we know it.
Depth perception is the visual ability to perceive the
world in three dimensions and in turn, the distance of
an object.
1. Distances are perceived solely by what is referred to as a
depth or distance sensation
2. Depth of field (thickness) of an object is not perceived
because of single line of sight

Color Perception
Horses have fewer cones (color receptors) than humans. This type of
vision, called dichromatic, causes the horse to perceive colors as
yellowish greens and bluish purples

Light Perception
Horses have more rods, light receptors, than humans and
perceive light much brighter than us

The result of 30% more light and 40% less color

Horses have trifocal vision, due to graduating gradients on
the horses crystalline lens

18 inches to 5 feet
for near vision
5 feet to
25 feet
25 feet to ~ for
distant vision
The horse’s vision is divided into three progressive
quadrants similar to a “trifocal” lens.
Middle area of the eye Bottom area of the eye
Upper area of the eye

These quadrants of vision are known as
“Area of Focus”
Middle area
Bottom area
Upper area

If the horse head is positioned at a constant angle,
the perception object distance and size is a relative
constant.

Central vision is that portion of the horses field of vision
where images tend to be more sharp and are recognizable by
the brain

Peripheral vision is the area that extends approximately
120-140º off the side of the horse
Peripheral vision reacts more to color,
contrast, movement, or light
Area of
Peripheral Vision
Area of
Peripheral Vision
Area of Focal Ability

As humans, we think of vision in terms of the ability to
focus.
However, another difference in equine vision is the structure
of the equine eye in that it is structured to detect motion
instead of focus. As a prey animal with its eye set, it can
detect this motion and most of their surroundings with only
slight head movement

As the object in the horses’ sight moves behind their area of focal
ability (forward) and into peripheral vision (off to the side), their
ability to focus is diminished.
Not only is the vision diminished,
The lack of focus makes the object
appear larger due to diffusion of light

The thought process of your horse is unlike,
but not entirely dissimilar to humans

Though the equine brain has two hemispheres (both
left and right), the two sides of the brain are
connected by a very underdeveloped Corpus
Callosum. This basically means, not only is equine
vision monocular, each side of the brain individually
processes sensory information. In other words, each
side “thinks” independently of the other.

If danger is perceived on either
side, the two sides of the brain
have different priorities. The side
that perceives the danger will
calculate where the danger is
regarding the “flight path” while
the other “brain” detects the
best escape route.
DANGER!!!!
Escape Route is 180 degrees in
the opposite direction

Escape Route is Behind and Right
Escape Route is Forward and Right
Escape Route is Behind and Left
Escape Route is Forward and Left

Escape Route is
Forward, Right and Low
Escape Route is
Forward, Right and High
Escape Route is Backward,
Right and Low
Escape Route is Backward,
Right and High

What this means to you
• 1. How to “set up” your hands and position
• 2. How to position your horse
• 3. How to maintain control
• 4. How to show your horse that the obstacle is NOT
the enemy
• 5. How to leave the obstacle behind without
“running away”

 Obstacle is it ahead or behind

 Obstacle is it lower or higher
Setting your Position

How to position the horse
• Move your horse
so he can see the
obstacle with
both eyes
Obstacle
Remember the horse will
break away from what they
perceive as the source of
distress

How to maintain control
• No matter which way the horse attempts to turn, always
point him at the object. From that point, it doesn’t matter
whether he backs away from the object or not, only that he
face it.
• BOTH EYES------ BOTH BRAINS

Show your horse that the obstacle is
NOT the enemy
• By steadily applying appropriate pressure until the job is
complete, you will show your horse that the enemy is his own
unwillingness; not that of the obstacle. Once the obstacle is
complete, repeat until the horse is relaxed over the obstacle.

Equine Vision Explained

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Equine Vision Explained