
Successful cataract surgery saves vision of penguin at Chester Zoo
Munch, a four year-old South American Humboldt penguin living at Chester Zoo, had been struggling to feed himself and catch fish due to him not being able to see, with his poor vision a result of bilateral cataracts which left him bumping into other penguins and not being able to find food. Ophthalmologist and clinical director of Eye Vet Referrals, Iona Mathieson, took the lead in his treatment.
Iona said: “We go to Chester Zoo periodically to help with ocular cases but this was an extra special case for me because I love penguins. I’ve been in the veterinary field for almost 24 years and Munch is the first penguin I’ve operated on.
“We’re really happy the surgery was successful and he is now on the way to making a full recovery.”
The Linnaeus-owned Eye Vet Referrals clinical director carried out phacoemulsification cataract surgery on both eyes, which involved fragmentation of the crystalline through using ultrasound, before aspirating the emulsified material through a small incision. The procedure encountered only one problem – they don’t make artificial intraocular lenses small enough for penguin eyes! Fortunately, there is evidence to show that penguins can recover fine without lens replacement.
After the surgery the team checked Munch’s menace response to assess his vision, adopting an innovative, if not slightly unconventional approach, of using Iona’s orange operating theatre shoe in lieu of someone’s finger; just as well, as Munch could indeed see the shoe – and promptly bit it!

“It was a funny moment and a happy moment, as straight away we knew the operation had been successful and that Munch could go home to the zoo,” explained Iona.
“Like many of the staff at the zoo, our team has worked throughout the national lockdowns, so taking care of Munch was just the morale boost we all needed.
“Everyone wanted to see him and make a fuss of him, so much so we’ve even decided to sponsor him now.
The good news continues; Munch is back in the pool with the other penguins, and he can now see his food and his fellow penguins without bumping into them.
Munch and his life partner, Wurley – who are both named after well known confectionary and snack brands – are now incubating an egg, with keepers hopeful that they will soon have a chick. This is promising news, as the International Union for the Conservation of Nature (IUCN) classes Humboldt penguins as vulnerable to extinction.
“It’s an amazing feeling knowing that we’ve helped save him. He was the first thing that made me smile in a long time and caring for him was definitely the best part of my year. We can’t wait to visit him and the penguin colony now the zoo has reopened.”
“It’s an amazing feeling knowing that we’ve helped save him. He was the first thing that made me smile in a long time and caring for him was definitely the best part of my year. We can’t wait to visit him and the penguin colony now the zoo has reopened,” explained Iona.
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