Historic Cataract Surgery Restores Vision for Dublin Zoo Hippo

An 18-year-old hippopotamus named Imani has undergone a groundbreaking cataract surgery at Dublin Zoo, marking the first recorded instance of such a procedure on a common hippopotamus globally. The successful surgery aims to improve her vision and quality of life, allowing her to navigate her environment with greater ease.

The veterinary team at Dublin Zoo collaborated with external experts to perform the complex operation, which was the result of meticulous planning and preparation. Imani had been coping with a long-standing visual impairment, relying on her sense of touch to navigate her surroundings. Despite her adaptations, she faced challenges due to her limited vision, moving slowly and cautiously to avoid obstacles.

Since the surgery, the staff have observed significant changes in Imani’s behavior. She is now responding to visual stimuli, moving confidently through her habitat, and even running—an encouraging sign of her improved eyesight. Her recovery is being closely monitored with the help of a bespoke sensor bracelet, which tracks her movement and overall welfare post-operation.

Innovative Monitoring and Future Implications

The sensor, equipped with an accelerometer, provides real-time data on Imani’s activity over a 24-hour period. This innovative tool allows the animal care team to compare her normal behavior patterns against any variations that may suggest health issues. This approach is a pioneering welfare innovation for the species, developed in partnership with l’Oceanogràfic marine park in Valencia and the Spanish Autónoma University in Madrid. Together, they are creating an algorithm to validate the sensor data through live behavioral observations of Imani.

The significance of this surgery extends beyond Imani’s immediate welfare. Her case is set to be documented for publication in peer-reviewed veterinary literature, with the hope of inspiring other zoological organizations worldwide. By sharing their findings, Dublin Zoo aims to pave the way for similar interventions in the care of other animals.

Frank O’Sullivan, a veterinary surgeon at Dublin Zoo, described the operation as “a ground-breaking operation, and an extraordinary technical achievement.” He emphasized that the primary focus was always on Imani’s welfare. O’Sullivan noted, “An enormous amount of time and care went into preparing Imani for the surgery, and seeing the marked improvement in her quality of life has made it all worthwhile.”

Lucy Stratford, a behaviour and welfare scientist at the zoo, echoed these sentiments. She stated, “Imani has made remarkable progress post-surgery. Our teams have closely observed her, and it’s been great to see her become much more confident and active now that she has improved sight. It’s a powerful example of Dublin Zoo’s commitment to providing world-leading animal welfare.”

The Status of Common Hippos

Common hippos are native to sub-Saharan Africa, residing in rivers, lakes, and swamps with reliable water sources. They play a vital role in their ecosystems, shaping grassland structures and contributing nutrients to aquatic food webs through their waste. Despite their importance, common hippos are currently listed as Vulnerable (VU) on the IUCN Red List, facing a high risk of extinction due to habitat loss, poaching, and climate change. Their populations have declined by over 30% in recent decades.

Imani’s successful surgery not only represents a significant achievement in veterinary medicine but also highlights the ongoing efforts required to ensure the welfare of vulnerable species. The innovative techniques developed through her case may serve as a model for future wildlife care, contributing to the conservation and rehabilitation of animals facing similar challenges.