Three elderly king penguins have been fitted with custom-made eye lenses during surgery to remove cataracts in what is believed to be a world first procedure to improve their sight, according to a Singapore zoo.
In a statement Tuesday, vets with the Mandai Wildlife Group said the birds were among six elderly penguins to undergo cataract surgery two months ago and have since made a full recovery.
They include three king penguins age 20 and older, and three Humboldt penguins, ages 7 to 13, which live in Singapore’s Jurong Bird Park.
Cataracts, which causes cloudy areas in the eye that hinder sight, is a common age-related condition in both people and animals.
“We noticed the cloudiness in their (eyes) and moving about like they were having difficulty seeing things in front of them,” said veterinarian Ellen Rasidi, explaining the decision to remove the cataracts.
The king penguins received custom-made intraocular lens implants, said Gladys Boo, a veterinary opthamologist who took part in the surgeries, which she said marked “a milestone in veterinary medicine.”
The lenses were custom-made in Germany with precise measurements to fit each penguin’s eye – a process that took two months, Boo said.
“As a larger species, the king penguins have eyes large and stable enough to hold the custom lenses in place so we decided to pursue this world-first procedure to further improve their vision above removing the cataract,” she said.
Photos taken behind the scenes showed the delicate procedure, which Boo said was especially tricky for penguins due to their unique characteristics, such as a third eyelid that protects their eyes underwater but which tends to close under surgery.
Post-surgery, all six penguins had to remain out of the water and zookeepers administered eye drops twice daily.
King penguins are the second-largest species of penguin and are found in the Southern Ocean and sub-Antarctic.
While not endangered, they are protected under wildlife laws. They can weigh up to 18 kilograms (40 pounds) and reach up to 1 meter (39 inches) tall and can live up to 30 years in captivity.
Zookeepers and vets said they observed “an increase in responsiveness and activity levels” in the penguins following the surgery.
“It is nice to see them more active, indicating their improved vision,” said Rasidi, the vet. “The king penguins are adapting well to the new lenses as well.”
Singapore’s world renowned Jurong Bird Park housed some 3,500 birds including parrots, flamingos and eagles before it shuttered its doors last August to prepare for a move to new premises, where it will join the city’s zoo and night safari and a new luxury resort to form an eco-tourism hub.
The park has been involved in several high profile rescues and rehabilitation efforts over the years – including treating a hornbill with cancer by fitting it with a 3D-printed prosthetic beak.