How much do you know about horse eyes?
1. Horse's Visual Range and Blind Spots
Horse's visual range: You might not know that the horse's eyes are the largest among mammals, being about twice the size of the human eyeball. Human eyes have a 180-degree visual field, facing forward, while horses have both monocular and binocular vision. Monocular vision means that each of its eyes can process 130 to 140 degrees of visual information on its own, while binocular vision is focused in front and can reach 75 to 95 degrees. This allows horses to have panoramic vision, nearly achieving a 360-degree panoramic mode.
Horse's blind spots: Horses have visual blind spots behind them, above the forehead, and below the mouth. When you see a horse raising its head, it is not because it is tired, but because it wants to observe something far ahead. When it lowers its head, it is to observe something close. If you suddenly try to touch its forehead, it will panic and pull away because it cannot see your hands.
2. Horse's Color Discrimination Ability
Horses, unlike humans with trichromatic vision, only have dichromatic vision and can only perceive changes in colors based on blue and green. They cannot distinguish red and are unable to differentiate variations in red colors.
3. Horse's Night Vision and Response to Light Intensity Changes
Behind the retina in the horse's eye, there is a layer called the tapetum lucidum, which reflects light that enters the eye back onto the retina, thereby enhancing the horse's ability to see in low light. Even with faint light, the reflection from the tapetum makes objects appear clearer to the horse.
4. Horse's Visual Perception of Distance is Poor
As is well known, we evaluate the distance to objects through binocular vision, but horses have a narrower binocular vision range and do not have as broad a monocular vision, so they mainly see flat images. Lacking a sense of depth, horses have poor distance judgment. This is why horses may become frightened when needing to jump over an obstacle, which is why long-term training and reinforcement are required to help them in such activities.
5. Horse's Tears and Symptoms of Illness
Horses' tears are mostly drained through the nasal cavity. The tears secreted by the lacrimal glands and third eyelid serve to moisten the eyeball. The lower eyelid collects the tears and they flow into the open nasal cavity through the nasolacrimal duct. So if you see a horse's eyes watering, it indicates that its nasolacrimal duct is blocked, causing the tears to flow down the cheek instead of entering the nasal cavity.
If a horse's eye turns blue, it means that its eye is injured. Under normal conditions, the cornea of the eye is transparent, but if injured, the cornea swells. When the swollen cornea reduces clarity, it turns blue. Immediate medical attention is needed.
