Abstract

Ocular diseases are reported in both free-ranging pinnipeds and those under professional care.^1,2,3,4,5 Intraocular pressures (IOP) are part of any complete ophthalmologic examination, but limited data exists from free-ranging pinnipeds.⁶ Between 2010–2016, IOP was measured using rebound tonometry (TonoVet, Jorgensen Laboratories) in 108 South American fur seals (Arctocephalus australis; 81 adults, 27 juveniles) and 37 adult South American sea lions (Otaria flavescens) at Punta San Juan, Peru. Animals were anesthetized for concurrent population health projects using isoflurane only; medetomidine, midazolam, and butorphanol (MMB); MMB + isoflurane; or alfaxalone. Animals in abnormal health or with gross ocular abnormalities were excluded from data analysis. A series of multivariate general linear models (MANOVA) was performed with IOP of the right (OD) and left (OS) eyes as dependent variables, and species, sex, age (adult, juvenile), year, and restraint method as the main effects to determine factors affecting IOP. Results show that age was the only factor associated with significantly different IOP (p<0.001). Juveniles had lower mean IOP than adults (Table 1). This finding is dissimilar to canine studies that show no difference between juveniles and adults,⁷ but consistent with Humboldt penguins, another marine species, in which chicks exhibit lower IOP.⁸ There were no significant differences in IOP among species, year, sex, or restraint method. The mean IOPs in this study are similar to California sea lions (32.8 ± 3.2 mm Hg) under professional care.⁶ This is the first study to the authors' knowledge reporting IOP in wild pinnipeds.

Table 1

Acknowledgements

The authors thank Marco Cardeña, Franco Garcia, Maria José Ganoza, Paulo Colchao, John Pauley, Kate Sladek, Mary Ann Duda, Ashlee Webb, and Jenny Meegan for their assistance with this project. We gratefully acknowledge support from SERNANP and facility access by Agrorural, as well as funding support from the Chicago Board of Trade Endangered Species Fund.

* Presenting author
+ Student presenter

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