Spotlight on Vet Medicine
January 13, 2009

Sight for a Giant Panda's Sore Eye

Giant pandas (Ailuropoda melanoleuca) are among the most charismatic and beloved animals in the world. And with fewer than 1,700 left in the wild and only 13 pandas living in America, each one is precious.

Tian Tian's red and swollen eye.

The National Zoo is home to three pandas: male Tian Tian, female Mei Xiang, and their three-year-old cub Tai Shan. Zoo staff and throngs of public admirers watch over all three avidly. So when Tian woke up one morning with a red, swollen right eye, one of his keepers noticed immediately.

Fortunately, Tian has been a healthy bear, so he hasn’t needed much medical treatment from the veterinarians during his eight years here at the Zoo. Tian’s keepers, along with veterinary staff have trained him to cooperate for all sorts of veterinary procedures, using treats such as pears, apples, or biscuits. He will sit still for injections and blood draws and will help vets examine his eyes and teeth. This sort of training is hard work and requires incredible patience from the keepers and from Tian, but it really pays off. Because Tian trusts his keepers so much and is comfortable getting veterinary exams through the mesh of his enclosure, the keepers and veterinarians were able to get a good look at Tian’s eye right away.

Tian gets eyedrops and a biscuit from one of his keepers.

Like dogs and cats and many kinds of reptiles, birds, and sharks, pandas have a “third eyelid,” called a nictitating membrane. This clear membrane protects and lubricates the eye. The membrane contains a tear-producing gland in the corners of the eyes. Veterinarians thought that this third eyelid had become very swollen, but they weren’t sure why.

Since Tian is such a well-behaved bear, the keepers were able to start giving him eye drops of antibiotics and pain medication to see if that would help the swelling go down. Despite his willing participation in his treatment (in exchange for biscuits), the swelling got larger, redder, and drier, and Tian began rubbing at his eye, as if wishing the irritation would just go away.

A veterinary ophthalmologist examines Tian's eye.

Zoo vets looked at Tian’s eye again after two days of the eye drops. Since the medicine wasn’t helping, they anesthetized Tian to give him a full exam, and a veterinary ophthalmologist (eye doctor) came in to help figure out what was wrong. Because the third eyelid was so swollen, the ophthalmologist was concerned that the growth might be a tumor. The veterinary team took a biopsy and sent it to Zoo pathologists for analysis. A few days later, the pathologists found that the mass wasn’t cancer, which was a relief to everyone. However, the ophthalmologist determined that the gland and the membrane were infected, and that they needed to remove some of each for Tian to recover.

Scientists don’t know much about giant pandas’ eyes. With so few giant pandas on the planet, there aren’t many to study. In dogs and cats, veterinarians know exactly how much of the gland they can take out and still leave the animal with a functional nictitating membrane, but with pandas, the vets were working in the dark. So, they decided to proceed very carefully. They cut out the swollen and infected portions of the membrane, but left as much as possible, hoping that that would be enough for the third eyelid to continue opening and closing normally, and protecting the eye.

After the surgery, Tian continued getting antibiotic eye drops and medicine for a few weeks. And, of course, his keepers kept an even sharper eye on him than normal. Happily, however, Tian’s surgery eye healed perfectly, staying as moist and healthy as it had been before the swelling occurred. Three months later, during a follow-up exam, zoo veterinarians concluded he’d made a complete recovery.

Visit Tian, along with Mei Xiang and Tai Shan in the Fujifilm Giant Panda Habitat.

Note to Media: If you would like more information about this project, or any of the Zoo's conservation and science programs, please contact the Zoo's Office of Public Affairs.

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