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In a groundbreaking veterinary feat, Edward, a youthful wolverine residing at the San Francisco Zoo, has become the first of his species to be fitted with a custom artificial eye lens. This innovative procedure was performed to address a vision impairment that threatened his quality of life.
At just two years old, Edward had already been through a cataract surgery. His caretakers had observed a troubling cloudiness in his right eye, a common sign of cataracts—a condition that blurs vision by clouding the lens. While cataracts are typically associated with older age, both in animals and humans, it was surprising to see such a condition in a wolverine so young, according to the Mayo Clinic.
“We did not expect to find a cataract in an animal of Edward’s age,” remarked Dr. Nick Dannemiller, a clinical veterinarian at the zoo. “It prompted us to consult with an ophthalmologist to better understand Edward’s eye health and needs.”
Edward, who has a particular fondness for taco seasoning, underwent a successful surgery. However, his caretakers noted the beginning of a cataract in his left eye as well. The surgery, while effective, could result in far-sightedness, giving Edward clear vision at a distance but causing blurred vision up close, which posed a challenge for a potential second surgery on his left eye. The veterinary team remains cautious as they consider the best course of action for Edward’s future care.
The taco seasoning loving wolverine’s surgery was successful but his left eye was forming a cataract. Because the surgery leads to far-sightedness, or blurry up close vision and clear distant vision, doctors were worried about doing the same surgery on his left eye.Â
Dr. Kate Freeman, a board-certified veterinary vision specialist who works with marine mammals, exotic animals and other captive wildlife, said Edward would not thrive with full far-sighted vision.Â
She, her mentor Dr. Christopher Murphy, from the University of California, Davis School of Veterinary Medicine, and his friend and colleague Dr. Donald Mutti from The Ohio State University College of Optometry worked together to make a custom fitted lens for the wolverine.Â

“I wasn’t about to pass on a wolverine case. Even though I’m a loyal Buckeye, I just couldn’t leave an innocent wolverine in the lurch,” said Mutti, referencing the Ohio State and Michigan mascots and the heated rivalry between those two universities. “Everyone deserves good vision.”
Murphy and Mutti had previously worked together to do the same for various birds. Dogs, humans and other animals can get the surgery with a lens to correct the far-sightedness.Â
Edward underwent a cataract surgery on his left eye and they put the custom-made lens in then. His caretakers say he and his right eye were doing well. Performing another surgery on the eye could introduce problems.Â
“Before the first surgery, he was very mistrusting of doing anything on the right side of his body,” said Dannemiller. “After the surgery, we believe he can see a bit better, albeit aphakic, because he was more willing to present his right side during training activities. And now after the second surgery, we notice improvements in his overall vision.”
Edward now gets eye drops three times a day, lives with his companion Molly and is expected to have a normal life.Â
Wolverines typically live about five to 10 years in the wild and up to 20 years in human care, Dannemiller said. Edward is one of roughly 30 wolverines in zoos in the United States. The species is listed as threatened under the Endangered Species Act due to climate change, habitat loss and a decreasing population.Â
