ESCRS - Cataract surgery on the eye of a tiger

Cataract surgery on the eye of a tiger

Indira had moderately crossed eyes, the beginnings of retinal degeneration, and thick, rock-hard cataracts on both eyes

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Dr. Cameron Whittaker[/caption] Dr. Cameron Whittaker is a veterinarian in Sydney, Australia, who specializes in eye care for animals. Indira, a 220-pound Bengal tiger, whose failing vision, along with Whittaker’s efforts to save it, became a challenging nine-month quest. She faced a delicate surgery, during with multiple possibilities for things to go wrong. Now 16, Indira lives in quiet retirement with other big cats at the Zambi Wildlife Retreat in Sydney.

Last year, Donna Wilson, Zambi's manager, noticed that Indira was eating less of her food. She bumped into things. Other cats began to pester her. Whittaker, who operates at the Sydney University Veterinary Teaching Hospital, conducted an exam. “She’s on one side of the fence and I’m on the other side,” he recalls. “We have to coax her up to the fence to get a good look. But obviously we have to be super-duper careful.” Whittaker found that Indira had moderately crossed eyes, the beginnings of retinal degeneration, and thick, rock-hard cataracts on both eyes. Without surgery, she would go blind. Indira's remarkable story is featured online in National Geographic.

EYE OF THE TIGER

Tiger eyes are among the most highly-evolved in the animal kingdom. Tigers find prey by glimpsing movement; often the slightest flick of a tiny paw is enough. Like humans, tigers have binocular vision, meaning they can judge distances with amazing precision. Their lenses are huge—four times the size of a human lens, allowing maximum light to enter the eye. As a result, tigers see six times as well as humans in twilight or darkness.

To see is to eat, even for tigers in captivity. If Indira’s vision could not be saved, she would have to be euthanized.

After the through-the-fence eye exam, Indira was transported to the University Veterinary Teaching Hospital in New South Wales in July and anesthetized for a battery of tests, including a CAT scan, MRI, and an ultrasound biomicroscopy. Because it’s never safe to anesthetize a big cat, veterinarians prepare for every potential diagnosis.

The same rule applies for surgery.

Whittaker and his wife, Kelly Caruso, who is also a veterinary ophthalmologist, planned two surgeries for Indira, one for the cross eyes and other for the cataracts. In November, Indira was again anesthetized while a team of veterinarians and human ophthalmologists gathered to fix the cross eyes. They made a surprise discovery. She had been treated for a parasite several months earlier, and by the time she arrived on the operating table, the cross-eye condition was less pronounced. The doctors concluded the parasite had inflamed the eye muscles and the treatment had eased the inflammation—and with it, the cross eyes. That left the cataract surgery. Artificial lenses were manufactured by a German firm and shipped to Sydney. In late April, Indira underwent the knife in a four-hour procedure Whittaker calls “the most difficult cataract surgery I have done.” The remarkable story of Indira is featured in http://news.nationalgeographic.com/2017/05/tiger-indira-australia-eye-surgery-animals/

For information on Cameron Whittaker http://www.cve.edu.au/speakers/cameron-whittaker