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Restoring Sight for Sita

Posted by: Rebecca Whitham, Communications with Laura McComesky, Zookeeper

Lion-tailed macaque, Sita, gets up close to her keeper’s camera. Photo by Andy Antilla/Woodland Park Zoo.

Monkey see, monkey do—and it's all thanks to cataract surgery that has successfully restored vision and quality of life to 29-year-old lion-tailed macaque, Sita (SEE-tah).

Going blind wasn't easy for Sita. In February, keepers first noticed in one of Sita’s eyes the tell-tale cloudiness characteristic of a cataract. Soon it was both eyes. The cataracts came on fast and worsened quickly, giving Sita very little time to adjust to this drastic change.

Sita’s left pupil was the first to appear cloudy in February 2014. Photo by Andy Antilla/Woodland Park Zoo.

As her eyesight disappeared, Sita struggled to do everyday tasks. Woodland Park Zoo’s lion-tailed macaque exhibit reflects the endangered species’ Indian forest habitat, with complex, arboreal pathways that suddenly became too challenging for Sita to navigate. At that point, she was moved behind the scenes where she could receive more close attention from her keepers.

Sita on exhibit. Photo courtesy of Harold Fox.

But even there she struggled. Sita's keepers would settle in next to the mesh divider to offer her a meal, and then wait patiently for 20, sometimes 30 minutes while she slowly, cautiously made her way over.  Not only had she lost her sight, but the experience also rocked her confidence. It was clear that the cataracts were affecting her quality of life as much as her vision.

Thankfully, there was hope. Our animal health team consulted with veterinary ophthalmologist Dr. Tom Sullivan at the Animal Eye Clinic of Seattle, and together determined that Sita was a good candidate for cataract surgery.

What exactly is a cataract? It’s a clouding of the lens—the part of the eye that focuses light—not uncommon in old age as proteins in the eye clump together. Cataract surgery is the removal of the clouded lens, which is sometimes followed by the installation of an artificial lens.

Cross-sectional view of right human eye. Courtesy of National Institutes of Health.

You've undoubtedly heard of this condition before as it occurs in humans and across the animal kingdom. In fact, just a few weeks ago, the zoo partnered with Dr. Sullivan to remove a cataract from a peregrine falcon's eye.

These kinds of health issues that are ubiquitous across the animal kingdom—cataracts, cancer, heart disease—will be the topic of the Zoobiquity conference at the University of Washington and Woodland Park Zoo this fall. We’re seeking to bring together human and animal health professionals to share knowledge and experiences. Sita's story is exactly the kind of case study that can unite doctors across the fields.

Sita at the animal hospital for her procedure. Photo by Andy Antilla/Woodland Park Zoo.

It took only a few minutes per eye to complete Sita’s procedure inside the zoo’s animal hospital. After Sita was anesthetized under the care of our veterinary team, Dr. Sullivan carefully removed the opaque lens from each eye using gentle suction.

A close up of Sita’s eyes. Photo by Andy Antilla/Woodland Park Zoo.

Once Sita awoke from sedation, zookeepers transferred her back to a holding area in the exhibit for further recovery. 

It didn’t take long before our hopes were affirmed—the monkey started to show signs of seeing once again! Since she no longer has eye lenses, Sita’s vision is not focused. But it still has made a notable difference in her ability to detect her surroundings and interact with others. 

To help Sita through her recovery, the keepers kept her behind the scenes with them for a few days while she finished up her post-surgery medication. We knew Sita was back to her old self when she was savvy enough to realize we were trying to sneak meds in her food. Turns out if you slip the medication into cookie mix, even tough-willed Sita can't resist.

Sita on exhibit. Photo courtesy of Harold Fox.

Sita has since returned back on exhibit and for the first time in months is able to navigate around on her own. She shares the exhibit with two males and one other female, Brie. Brie is a livewire compared to Sita, the laid back one. The two are figuring out their relationship all over again as Sita bounces back from her ordeal. She was once much more confident, but losing her sight for a time and going through recovery has made her more timid and tentative. Keepers expect her confidence will return as she readjusts to her sighted life.

For Sita, things are looking good.


Anonymous said…
This is wonderful!
Anonymous said…
It is truly a blessing today with the medical technology offered to all animals! This story of Sita shows how the quality of life is so important for every living creature. I think some humans forget that other mammals feel emotions just like us!
Emily said…
Dr. Sullivan is the man!
Anonymous said…
Took our domestic cat to Dr Sullivan.