Can horses inherit susceptibility to cataracts?

A Cornell University study suggests horses may inherit an increased susceptibility to cataracts. And some breeds are more likely to develop the problem than others.

What are cataracts?

A clouding of the normally clear lens of the eye, cataracts can impair vision. Cataracts may worsen over time, causing blindness.

Which horses are likely to develop cataracts?

For the study, researchers reviewed the records of 70 horses diagnosed with congenital cataracts (present at birth) or juvenile cataracts (developing when the horse is very young) at the university hospital. In 56 horses, both eyes were affected. The rest of the horses had a cataract in only one eye. In addition, the researchers found a breed connection. Quarter Horses, Andalusians and Standardbreds were significantly overrepresented in the study sample compared to the overall populations of horses treated in the ophthalmology department and at the hospital in general.

Researchers see a genetic connection

The researchers conclude that “the overrepresentation of certain breeds and frequent bilateral nature of congenital and juvenile cataracts [suggests] an underlying genetic basis.” They call for studies to identify the genetic variants associated with the condition. 

Reference: “Congenital and juvenile cataracts in horses,” 68th Annual American Association of Equine Practitioners Convention Proceedings, November 2022

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