A finely focused operation
Spark was placed under general anesthesia for the procedure. “Ocular surgery is delicate work in a very small area,” says Sandmeyer, “so we use a microscope focused directly on the eye to see what we are doing.”
Sandmeyer opened the laceration with a scalpel and pared off the ragged wound edges. She also removed the portion of the iris that had been projecting out of the globe. “The rest of the iris was still attached and healthy, so we just let that float back into the eye,” she says. “He’ll always be missing a tiny piece of it, but that won’t affect how the rest of it functions; his pupil will still dilate and constrict.”
Sandmeyer did a second vision
check of the lens to ensure it wasn’t ruptured or otherwise damaged. “If it had been, we could have removed it, leaving him really farsighted, or put in a prosthetic lens.”
Next, she flushed out the cloudy aqueous fluid and replaced it with a balanced salt solution. “The body generates eye fluid rapidly, and so within a few hours of surgery, the salt solution is replaced with healthy aqueous fluid,” she says.
Sandmeyer stitched the laceration closed with tiny sutures and created a conjunctival graft to protect the area. “We create a small stalk of tissue, from the conjunctiva around the eye,”
2014 she explains. “One end is still attached to the blood supply, but the other is sewn over the wound. This flap protects the area.”
Spark recovered uneventfully from the anesthesia and seemed to be able to see clearly right away. The next day the stallion was sent home with detailed instructions for three weeks of medication. “Medicating eye injuries can be very time-consuming and difficult,” says Sandmeyer. “He was getting multiple medications in his eye four times a day in the beginning. Eventually, horses start to object, and it can become quite the battle.”
To make the process easier, Spark was outfitted with an ocular lavage system, a narrow tubing placed under the eyelid and secured to his mane. Then, his medications could be injected into the end of the tube to be delivered directly into his eye.
After three weeks, Spark was returned to the clinic for a follow-up exam. “He healed really well,” says Sandmeyer. “The eye was clear and all our tests indicated his vision was functionally normal. There’s a lot that could have gone wrong in those three weeks; infection could have developed, and some horses end up damaging the eye again if they rub it on something. But his eye looked great.”
Conjunctival grafts, like Spark’s, are left in place indefinitely but do not interfere significantly with vision. “He has to see around it, but it’s very tiny,” says Sandmeyer. “And even if the graft wasn’t there, he’d still have the scar on that area blocking his vision.”
Despite how serious the injury had appeared at first, Spark’s positive outcome isn’t unusual, says Sandmeyer: “I know eye injuries can look really bad, but if you get help right away and are able to control the inflammation you’d be surprised just how well they can do.”
All the structures that support vision appeared to be intact and functioning, and indeed, Spark’s prognosis for regaining vision was good.