June 1, 2016 
We’ve all heard the familiar warnings about blue-eyed horses…
“They’re a special kind of crazy.”
“Can’t work them in the bright sun.”
“They’re a lot more prone to skin cancer.”
“Eventually, they all go blind.”
But is any of it true? You’ve heard it around the barn, from a vet, from your great granddaddy the cowboy and read it on the internet, so IT HAS TO BE, RIGHT?!
Come on…
A study conducted by the University of Illinois Veterinary Teaching Hospital has the myth-busting conclusion. Researchers studied the medical records of hundreds of horses—164 with diagnosed ocular disease and 212 without any known eye ailments—to determine if blue-eyed horses possess unique temperament qualities or are more prone to eye problems. So what did they find?
The team found that blue and heterochromic eyes were just as common as brown eyes in both groups of horses. The researchers found no significant difference between the proportion of blue and brown-eyed horses with problems in adjacent structures to the eye (such as eyelid lacerations and neoplasia), corneal disease (such as ulcerative and non-ulcerative keratitis), or disease in the eye or eye socket (including equine recurrent uveitis, glaucoma, cataract, intraocular neoplasia, orbital cellulitis, and orbital neoplasia).
“The most important takeaway from this study is that blue-eyed horses are not any more likely to get disease of the eyeball itself than brown-eyed horses,” said Labelle. “There is a common misconception that the blue color of their iris makes them more likely to get cataracts, have vision problems, or develop equine recurrent uveitis; this study demonstrates that this isn’t true.”
While this is no doubt good news for you blue-eyed horse owners, you’re not completely out of the woods. The study did find that blue-eyed horses appear to be more susceptible to squamous cell carcinoma (SCC) than their dark-eyed brethren. This is due to skin pigmentation around the eye and eyelid rather than the eye-color itself, which is why certain breeds are more prone to developing SCC.
©Flickr/digallagher
Do your part to protect your horses—blue-eyed or otherwise—from the harmful effects of UV rays. Fly-masks can help shield the face, and sunscreen obviously helps. Shade should always be available in turn-out space. Try to avoid exposing horses to direct sunlight at peak hours as much as possible.
And there you have it. Blue-eyes do not equal crazy. Unless they are crazy eyes that just so happen to be blue, then you might have an issue, but there is not a shred of scientific evidence to suggest a direct correlation between eye color and temperament.
Study: “Prevalence of ophthalmic disease in blue-eyed horses,” published in Equine Veterinary Education
