You make your turn and canter towards the blue oxer, hoping that your horse will find his distance and clear it without any problems. The only thing you think is ‘jump!’, but the only thing your horse is thinking is ‘Is that a jump or another horse…?’ or… ‘Man, I wish I had some glasses!’
It can happen, according to British researchers, horses do not always see sharply. Approximately two-thirds of horses have normal eyesight, but some are nearsighted and others are farsighted in one or both eyes. And this knowledge could increase safety and performance in the competition ring, the researchers say. “People are currently worried about fence design and what contribution this could have to the ‘usual’ accidents that occur in the various disciplines,” said Carol Hall, PhD, lecturer of equitation science at Nottingham Trent University in the UK.
“Although we are unable to eliminate all risks associated with riding, by understanding more about the differences between human and equine vision, we may be able to reduce the risks. Currently, fence design is based on how things are seen by people. We have to look at things from the horse’s perspective.”
And although that does not necessarily mean that horses will soon wear contact lenses or Armani spectacles, it does mean that science can help people to create fences that are better adapted to the horse’s vision. It also means that eye examinations could help in selecting young horses with good vision for the sport. In the study, Hall and her fellow researchers performed a retinoscopy on 333 horses and ponies of different breeds. Retinoscopy determines how good a horse’s vision is. Their findings were that 68% of the horses had ‘perfect’ vision (‘normal vision’) in both eyes. Of the vision problems, about half were nearsighted and half were farsighted, Hall said.
“We wanted to test whether there was indeed any evidence that horses became more nearsighted as a result of their relationship with people (because of domestication, horses were removed from large plains where hypermetropia might be an advantage). We found no consistent evidence that horses tend to be hypermetropic or myopic, which is good news for the riders, I think.”
Yet individual horses could be influenced by their environment, despite the genes they have, Hall added. For example, weaned foals kept in confined spaces (such as stables and small paddocks/fields) may not fully develop their vision if they do not ‘practice’ this by looking far away. “The visual system will adapt to what is required, so gaining visual experience at as many different distances as possible will help improve vision.” she said.
Hall said that an interesting finding from the research was the difference between the various breeds. Warmbloods and draft horses (especially Shires) tended to be more farsighted, while thoroughbred crosses were more myopic. This probably had to do with the shape of the head and the position of the eyes in these breeds, she said. The researchers also noted major differences between the two eyes on a number of horses, which can affect how horses respond to work (preference for a particular side), how they spook and even how they take naps, Hall said. “This is just another example of how more information about the horse’s vision could help us better understand the horse’s behaviour,” she said.
An important conclusion of the study was that although people’s vision differ from horses’, it does not mean that one is better or worse than the other, Hall said. “We will continue to test the eyesight of horses to continue our journey into looking at the world through the eyes of a horse.”
The study ‘A retinoscopic survey of 333 horses and ponies in the U.K.’ has been published in Veterinary Ophthalmology.
Article source: Thehorse.com
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