If a horse injures the anterior part of his eye—the portion from the lens forward—or otherwise develops a problem there, it’s usually obvious. He squints or has a weepy eye, and clouding, discoloration, or even a lesion on the eyeball surface might be apparent. But whether there are issues with the back of the equine eye can be a little more mysterious, even to the examining veterinarian.

Professor Derek Knottenbelt, OBE, BVM&S, DVM&S, Dipl. ECEIM, MRCVS, polled practitioners during his presentation at the 2016 British Equine Veterinary Association Congress, held Sept. 7-10 in Birmingham, U.K., on their confidence in pinpointing posterior segment issues. Their responses showed that, indeed, diseases of this part of the eye are largely an enigma. These conditions are important to understand, however, because they can ultimately threaten a horse’s vision.

Knottenbelt, an affiliate and equine consultant in veterinary pathology, public health, and disease investigation at the University of Glasgow, in Scotland, shared what he has learned about posterior uveitis—that is, inflammation in the back of the eye–with the goal of finding a strategy to help veterinarians document these cases.

He said posterior uveitis is:

  • Very easily overlooked “Most cases are detected incidentally, you aren’t expecting anything,” he said. “So, in other words, it tends to be a prepurchase examination finding or an insurance examination finding, or when you look at the eye because it’s bashed its head. There’s an incredible dilemma for us all in assessing th