Focusing on Smooth-Sided Toad Eyes

The smooth-sided toads of Upland Tropical Rain Forest are part of a study to document important medical information about their eyes—first-of-its-kind research for this species.

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The smooth-sided toads in Upland Tropical Rain Forest are one of the lesser-known residents of the exhibit; although they roam the habitat freely, they only emerge at night. Every few years, in what's become known as a "toad-eo," Aquarium herpetologists conduct a nighttime roundup of these amphibians so they can perform routine medical exams.

Last year, however, our experts were able to perform these exams without a rain forest roundup. In spring 2022, as part of the renovation to the glass pyramid topping Upland Tropical Rain Forest, the majority of exhibit residents found a temporary home at our Animal Care and Rescue Center until the rain forest reopened later in the year.

My, What Large Eyes You Have!

Like many other nocturnal animals, smooth-sided toads have large eyes to help them see better in the dark.

While the smooth-sided toads were in our state-of-the-art facility, our experts not only performed their standard medical exams—they also took advantage of the opportunity to conduct research. National Aquarium Veterinary Fellow Sarah Balik led the charge on conducting an ophthalmic—in other words, related to the eyes—study with these amphibians that aims to establish what a healthy, normal eye looks like for a smooth-sided toad.

This study is the first ever to describe the morphology of eyes in this particular species and it documented critical medical information, including intraocular pressure, tear production and the normal bacteria that can be found on the healthy eyes of smooth-sided toads.

Veterinarian Looking Though a Slit Lamp at a Smooth-Sided Toad's Eyes
Dr. Micki Armour, a veterinary ophthalmologist our team partnered with for the study, uses a slit lamp to examine a toad's eyes.

According to Sarah, ocular issues are quite common in amphibians. "In general, these animals are predisposed to ocular issues because of the anatomy—they have large eyes, and the relatively short shape of their eyelids is not quite as protective as in other species," she explains. "This can predispose them to trauma or injury to the eyes."

Under Pressure

A device called a tonometer measures pressure inside the toads' eyes. Measuring intraocular pressure—that's the pressure of fluid in the eye—is a particularly important part of an eye exam for any species because a change in eye pressure can indicate issues such as glaucoma or inflammation.

It's important for our experts and others in the field to understand the 'normal' for this species' eyes because having a medical baseline will help veterinarians diagnose—and ultimately treat—eye-related conditions, including infections and glaucoma, in smooth-sided toads.

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