A retrospective survey of the ocular histopathology of the pinniped eye with emphasis on corneal disease

Objective A retrospective review of globes from 70 pinnipeds submitted to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW) describing the type and frequency of ocular disease. Animals studied The study included 50 California sea lions, four animals listed only as ‘sea lion’, nine Northern elephant seals, five harbor seals, 1 Northern fur seal, and 1 Hooded seal. Procedures Globes were classified by microscopic findings. Categories were not mutually exclusive. Results The largest category was corneal disease (63 globes from 40 pinnipeds). The second largest was cataractous changes (35 globes from 23 pinnipeds). Additional ocular diseases included traumatic ocular injuries (nine globes from eight animals), phthisis bulbi (nine globes from eight pinnipeds), neoplasia (nine globes from six adult California sea lions), amyloid deposition in the corneal stroma, ciliary body, or both locations (five globes from four pinnipeds), and fungal disease (three globes from two pinnipeds). Pinnipeds with corneal disease were further categorized: stromal pathology (39 globes from 27 pinnipeds); epithelial pathology (37 globes from 27 pinnipeds); Descemet’s pathology (11 globes from eight pinnipeds); endothelial attenuation or absence (33 globes from 22 pinnipeds); presence of retrocorneal membranes (15 globes from 10 pinnipeds); anterior synechia (eight globes from six animals), and keratitis (seven globes from five pinnipeds). Conclusions This is the first report of ocular amyloid in pinniped eyes. All cases of neoplasia were in a pattern suggesting metastatic disease. In this study, there was a higher prevalence of ocular disease in captive pinnipeds, particularly in the posterior cornea.