Did you know that a horse’s eye is eight times bigger than a human eye, and one of the biggest possessed by a land mammal?
That, however, isn’t anywhere near the only difference between human eyesight and equine eyesight.
Horses have monocular and binocular vision. They can’t use them both at the same time, but must switch from one type to another by repositioning the eyes and head.
Horse’s eyes are also located almost laterally on the side of its face, giving them a huge range of vision.
Monocular vision means that they can see with each eye independently – giving them the ability to see what is happening on each side of their body. This vision is flat, unlike the three-dimensional vision humans have.
Equine veterinarian Dr Charlie El-Hage, who spent decades working in practice, described a horse’s eyesight as “phenomenal.”
Dr El-Hage has returned to the University Of Melbourne Equine Centre as a lecturer and said humans couldn’t relate to a horse’s eyesight and the scope and power of it.
“They have almost 350-degree vision. They get so much input it’s very difficult for them to focus on what’s in front of them. It’s something we can’t relate to,” Dr El-Hage said. “We don’t have that degree of vision.”
Dr El-Hage said the 350 degrees of vision is made up of 285 degrees of binocular vision and 65 degrees of monocular vision.
“They have almost 350-degree vision. They get so much input it’s very difficult for them to focus on what’s in front of them." - Dr Charlie El-Hage
“They see so much. They have such good eyesight. It’s difficult for them to focus on what’s in front of them,” he said.
Dr El-Hage said horses were built like this as they were flight animals.
“Horses are so athletic they are built to run and to react to predators. They are unique and have a flight response – they are built for speed and flight,” he said.
“A horse’s vision is compromised a bit because although they can focus on something, generally they are bombarded with input from all around.”
Dr El-Hage said that head gear on horses such as blinkers, winkers or nose rolls was designed to change their vision and to help them focus.
“They restrict their vision by giving them lesser input. They won’t spook at something they can’t see and it helps them to concentrate,” Dr El-Hage said.
“It limits their visual input and that can be a good safety measure, but not with every horse.”
Renowned jumps trainer and former Australian show jumping champion rider Eric Musgrove said the horse’s eyesight was amazing.
“When I was show jumping you could canter and do a single strand of rope probably a metre high just in the dark – their eyes are a lot better than people think,” Musgrove said.
One of the favourite gear changes a trainer can use is blinkers and both Musgrove and another reputed trainer Symon Wilde said placing them on a horse in a race helped it to focus.
“I think it helps. Horses we ride around our paddock at home, if they are looking around and not concentrating, that’s usually when we use blinkers,” Wilde said.
“I think they respond to the riders better when they have blinkers on.”
Mornington equine veterinary surgeon Dr Eoin Kelly said horses could race with one eye such was the extent of their vision, but it was banned in Australian racing.
Dr Kelly said in the USA, three-year-old Uno Ojo was a Grade 2 winner earlier this year who had lost his eye as a yearling in an accident (his name was inspired by his predicament, with ‘uno oja’ translating to ‘an eye’ in Spanish).
Another horse in the USA, Pollards Vision was also a Grade 1 placegetter and raced with one eye.
He also pointed out there had been several smart showjumpers who jumped successfully with vision in one eye.
Kelly believes the rules in Australia should be reconsidered, believing that there are many one-eyed horses’ that could race successfully.
