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Flat-faced dogs at risk of blindness, a new study reveals

Close up of Boxer dog looking at camera
(Image credit: Getty Images)

They’re trendier than a Chanel handbag right now, but vets are warning pet owners that the surge in demand for flat-faced dogs is leading to blindness as a result of overbreeding. With their bulging eyes and cute looks, breeds such as Pugs and French Bulldogs are becoming more and more popular, but researchers have found that changes to the shape of their skulls are putting their vision at risk.

In a study conducted by a team of vets from Lisbon and Leipzig universities, half of the 93 flat-faced dogs examined, including Pugs, French Bulldogs, Shih-Tzu’s, Boxers, and Pekingese, were found to have macroblepharon, an abnormally large opening of the eyelids. When combined with the way their eyes distinctively bulge, the eyelids become impossible to close. 

"As these breeds grow in popularity, veterinary hospital teams are treating more and more dogs of brachycephalic [flat-faced] breeds with a wide variety of problems caused by breeding for a characteristic short-nosed flat-face," the research team explain. 

Just as studies have shown that flat-faced cats can’t show emotion due to selective breeding, flat-faced dogs are also suffering the consequences of human tampering. Already struggling with a wide range of health conditions, including breathing and walking difficulties, their increase in popularity is leading to unsafe breeding practices that put their health further at risk in an attempt to keep up with demand.

“Their personalities, wrinkly faces, and appealing large eyes have turned them into popular pets," the team explains. "This popularity is thought to exist because humans find the large and round eyes, as well as the round face very appealing." While they understand the draw of these features, overbreeding is causing irreversible trauma, ulcers, and erosion of the eyeball that over time results in vision loss.

The vets found entropion, a condition where the eyelid turns inwards and causes the eyelashes to rub the eyeball, in 20 of the dogs, while ulcers on the cornea were found in 41 of the dogs. Cornish pigmentation, where a blackish pigment spreads across the surface of the eye causing blindness, affected 33 of the dogs, with Pugs being the worst affected. Corneal fibrosis, or scarring, was found in 23 of the dogs, with the majority being French Bulldogs and Shih-Tzu’s. 

Researchers concluded that overbreeding has resulted in serious changes to the structure of the skull in these breeds, leading to protruding eyes with exposed surfaces. While French Bulldogs were the worst affected, with Pugs close behind, almost all the flat-faced dogs included in the study had some degree of vision impairment and it’s causing alarm amongst vets. 

"The number of these patients is increasing in small animal practices and our study has highlighted the importance of responsible breeding, early diagnosis, and regular ophthalmic check-ups to correctly diagnose, treat and if possible prevent situations of irreversible blindness in these patients".

Kathryn Rosenberg

Kathryn is a freelance writer with a passion for creating health and wellness, travel and wildlife content. Originally from New Zealand, her nomadic lifestyle has her currently fur baby-less. She scratches her pet parent itch by stealing frequent cuddles with any neighbourhood cat kind enough to indulge her.