About a year ago, reptile keepers at Melbourne Zoo first noticed changes to the eye in one of their crested basilisk lizards. Fatty deposits had started to appear, making the eye appear cloudy.
On closer inspection they saw the same thing was happening with the other two crested basilisks – and zoo staff had a mystery on their hands.
Senior vet Dr Helen McCracken ordered blood tests for the reptiles, which otherwise appeared healthy. The results for each animal came back the same. These small lizards, which originally hail from the Americas, had high cholesterol.
On Friday Anu O'Reilly, a veterinary ophthalmologist from the Animal Eye Care clinic in East Malvern, paid a visit as part of their annual check-up.
Dr O'Reilly said the high cholesterol readings explained the fatty deposits in the cornea, the front clear window of the eye.
A type of iguana, the three crested basilisk lizards are now on an adjusted diet of "low-fat" insects.
Dr McCracken said although staff were not exactly sure what had caused the high cholesterol readings, the animals were now being fed "leaner" insects.
"The insects we feed the lizards are given a particular food before being fed to the lizards and that food has been modified to reduce the fat content," Dr McCracken said.
Also receiving attention from Dr O'Reilly on Friday was nine-year-old Mary, a wombat with a cataract in her right eye.
Cataracts are rare in wombats and Dr O'Reilly said it was most likely to have been caused by trauma – probably from being hit by a car. Of most concern was whether the cataract had developed into glaucoma, a painful condition that can be triggered by inflammation of the eye.
"I'm pleased to report that that's not the case," Dr O'Reilly said following Mary's examination.
Some seals, an elderly coastal taipan and a star tortoise were also seen by Dr O'Reilly as part of her annual rounds at the zoo.
She said it was important to maintain eye health because while the animals are living in captivity they need to lead interesting lives as a way of maintaining well-being.
"We want to provide opportunities for them to search for their food and interact with other animals, climb and burrow," she said. "If evolution says you need sight for that then we want to preserve sight."
