The Use of Thermal Keratoplasty to Successfully Treat Refractory Bullous Keratopathy in a Northern Fur Seal (Callorhinus ursinus)
Corneal diseases, such as bullous keratopathy, are the most common form of ocular pathology in captive pinnipeds.1 Thermal keratoplasty is a technique used in humans and, more recently, in domestic species, to treat bullous keratopathy. A thermal keratoplasty was performed under general anesthesia on a 23-year-old northern fur seal (Callorhinus ursinus) female with an eight-month history of moderate to severe (5 to 30 mm in diameter) corneal bullae, and subsequent corneal ulcerations. The thermal keratoplasty was performed with a hand-held cautery unit. Twenty-eight pinpoint superficial corneal stromal burns were applied over a short period (total procedure < 5 minutes) to create adhesions between the collagen layers of the cornea. The animal was allowed normal saltwater access 48 hours postoperatively and returned to exhibit at day 10. Postoperative medical management included oral meloxicam (0.1 mg/kg q 24 h), oral tramadol (4 mg/kg q 12 h), and topical Besivance (2 drops q 8 h) via a voluntary eye drop behavior. At day 13, there was minimal corneal edema with no blepharospasm and an intact corneal epithelium. There was no recurrence of bullous keratopathy post thermal keratoplasty for the duration of the animal's life (~ 1 yr). Ocular disease was limited to mild intermittent uveitis, likely secondary to a lensectomy performed 4 years prior, and was managed with short courses of oral nonsteroidal antiinflammatories, oral tramadol, and topical ophthalmic nonsteroidal antiinflammatory medications. The animal was humanely euthanized for nonocular-related reasons, and histopathology was performed on both eyes. To the authors' knowledge, this is the first application of thermal keratoplasty to treat a common ocular disease of captive pinnipeds.
The authors would like to thank Dr. James Bailey, National Marine Mammal Foundation; Dr Carmen Colitz, All Animal Eye Care, Inc.; and Dr. Martin Haulena, Vancouver Aquarium.
* Presenting author
1. Miller S, Colitz C, St. Leger J, Dubielzig R. A retrospective survey of the ocular histopathology of the pinniped eye with emphasis on corneal disease. Vet Ophthalmol. 2013;16(2):119–129.