Penguins are pelagic birds that reportedly live up to 40 years.1 The authors currently care for 50 penguins over age 35, the oldest being an emperor penguin (Aptenodytes forsteri) at 49 years old. Cataracts are the most reported age-related pathology in penguins.1 The current study compared ultrasonographic images of healthy penguins from nine species (n=143; 275 eyes) from two facilities to establish normal anatomy and biometrics. Eyes were scanned using B-mode ultrasound in transverse and sagittal planes without the aid of a stand-off pad. Globe length was correlated to body mass and differed significantly by species, with emperor and king penguins (Aptenodytes patagonicus) having the largest absolute diameter (mean 2.91 cm ± 0.06 and 2.74 cm ± 0.17, respectively), but the smallest relative to body mass. Humboldt (Spheniscus humboldti) had the smallest absolute diameter (1.66 cm ± 0.06) and the largest pecten to globe length ratio, while Southern rockhoppers (Eudyptes chrysocome) had the largest globe length relative to body mass. Lens to globe length ratio was largest in kings. Antemortem ultrasound images of birds with ocular pathology were also reviewed against postmortem histopathology. Ultrasound is a safe, fast, and noninvasive diagnostic tool that can effectively assist diagnosis and grading of cataracts, postphacoemulsification monitoring, and investigate posterior chamber and retinal pathology that may be difficult to appreciate with direct or indirect ophthalmoscopy alone.
Acknowledgements
The authors wish to thank Dr. Nancy Stedman, Dr. Rebecca Rivera, Brittany Dolan, Morgan Reitano, Alexandria Mena, Tara Klimek, Amanda Throckmorton, Katie Buckner, Andra Kurtz, Elton Molina, Jared Saldana, and the entire aviculture and husbandry teams of SeaWorld San Diego and SeaWorld San Antonio, as well as the staff of the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW).
*Presenting author
Literature Cited
1. Stidworthy MF, Denk D. Sphenisciformes, gaviiformes, podicipediformes, procellariiformes, and pelecaniformes. In: Terio KA, McAloose D, St. Leger J, eds. Pathology of Wildlife and Zoo Animals. London: Elsevier. 2018;649–681.