Abstract

Otariid keratopathy is a recurrent progressive disease that affects otariids; i.e., sea lions and fur seals. Clinically, the disease begins as a faint corneal opacity just dorsotemporal to the flattened plateau or at the temporal limbus with or without superficial indolent corneal ulceration resulting in pain, inflammation, stromal loss and, in some cases perforation, and secondary cataract formation. Due to environmental opportunistic bacteria and yeast/fungal organisms, the lesions are prone to infection. Risk factors for this disease include salinity below 33 ppt and the concurrent use of ozone and chlorine; protective factors include having no history of trauma, no previous eye disease(s), UV index below 6, and being under 20 years of age. The recurrent nature of the disease, lack of an immune response, and minimal to no vascularization suggests an ocular surface immune imbalance. Topical cyclosporine and tacrolimus are specific immunomodulatory drugs that inhibit T lymphocyte activation, improve aqueous tear production, and increase mucin production. The use of subchoroidal cyclosporine (CSA) implants have been used in horses with equine recurrent uveitis for approximately 20 years, and episcleral implants have more recently been used in dogs with keratoconjunctivitis sicca and other surface immune mediated ocular diseases.

Over the past almost 6 years, episcleral cyclosporine implants have been placed in eyes of 57 sea lions and fur seals, specifically 27 California sea lions (Zalophus californianus), 9 New Zealand fur seals (Arctocephalus forsteri), 7 Australian sea lions (Neophoca cinerea), 6 Subantarctic fur seals (Arctocephalus tropicalis), 4 South American sea lions (Otaria byronia), 3 Australian fur seals (Arctocephalus pusillus doriferus), and 1 Steller sea lion (Eumetopias jubatus)., specifically 27 California sea lions (Zalophus californianus), 9 New Zealand fur seals (Arctocephalus forsteri), 7 Australian sea lions (Neophoca cinerea), 6 Subantarctic fur seals (Arctocephalus tropicalis), 4 South American sea lions (Otaria byronia), 3 Australian fur seals (Arctocephalus pusillus doriferus), and 1 Steller sea lion (Eumetopias jubatus). Forty animals had concurrent lensectomy and 17 animals only had CSA implants placed. There were 29 females and 28 males in this group ranging in age between 0.67 years to 29 years of age (average age 15.9 years), at the time of procedure. Two animals, one California sea lion and one Subantarctic fur seal, had 2 sets of implants placed at different surgical events. One eye of one animal had 3 implants placed, and one animal had implants changed periodically due to potentially not working anymore. Two animals recently had implants placed; therefore, no conclusions on these animals can be made at this time. Forty-nine animals (86%) have had few to no flare-ups of otariid keratopathy since getting the CSA implants, as per the medical records and compared to prior to implants and compared to other animals without implants. One animal has continued to have uncontrolled keratopathy and a second set of implants will be placed. Results from seven animals are still pending. Therefore, use of CSA implants has been able to positively impact this recurrent frustrating disease. It will be important to monitor otariids that received implants at a young age and see if they have overall healthier corneas, develop cataracts later than normal, and continue to have controlled disease.

* Presenting author