Carbon Dioxide Laser Keratoplasty for Treatment of Chronic Bullous Keratopathy in a California Sea Lion (Zalophus californianus)
A 21-year-old female California sea lion with bilateral cataracts exhibited OS blepharospasm, intermittently severe corneal opacity, and discomfort. The sea lion had a history of one episode of OS keratitis with punctate ulcerations 1 year previously which had responded to medical therapy, as well as OS lens induced uveitis which was also controlled by medical therapy. Ophthalmic examination under general anesthesia revealed OS bullous keratopathy with secondary multifocal punctate superficial ulcerations. Medical therapy was attempted but response was marginal, controlling some discomfort but not resolving bullous keratopathy. Carbon dioxide (CO2) laser keratoplasty was elected as possible definitive treatment. A CO2 laser scanning head was used to diffusely contract the anterior corneal stroma to prevent bullae and subsequent ulcer formation. Postoperative corneal epithelial healing time (12 weeks) was prolonged compared to thermokeratoplasty in domestic animals and one previously reported sea lion thermokeratoplasty procedure.1,2 Significant postoperative behavioral complications including severe aggression and anorexia occurred, and were attributed to changes in management such as restricted water access and increased frequency of medication following the procedure. These behavioral complications limited topical and oral therapeutic options, which likely impacted healing time. Despite complications, successful resolution of bullous keratopathy, improved corneal clarity, and reduced pain were achieved. CO2 laser keratoplasty can result in improved quality of life for sea lions with refractory corneal disease, but behavioral and training characteristics of individual sea lions can have significant impact on postoperative healing period.
1. Dumonceaux G, Barrie K, Chittick B, Andrews S. Thermokeratoplasty in a captive California sea lion (Zalophus californianus). In: Proceedings of the International Association of Aquatic Animal Medacine. 2003:153–154.
2. Michau TM, Gilger BC, Maggio F, Davidson MG. Use of thermokeratoplasty for treatment of ulcerative keratitis and bullous keratopathy secondary to corneal endothelial disease in dogs: 13 cases (1994–2001). J Am Vet Med Assoc. 2003;222(5):607–612.