Corneal lesions in captive California Sea Lions (Zalophus Californius) The diagnostic aid of fluorescein and the influence of water quality on the cornea.

Abstract

Corneal opacities and corneal ulcers are frequently observed in captive California sea lions. The objective of this research project was to investigate the influence of water quality on these eye problems. The diagnostic aid of fluorescein dye in corneal defects was also tested. For six weeks two sea lions and their corneal lesions were followed and water quality (Chlorine, salinity and pH) was tested every day. It appeared that the concentrations of total, free and combined Chlorine had a significant influence on the size of the corneal lesions, whereas combined Chlorine had the most significant influence. It also appeared that not all the lesions were positive with fluorescein. However, fluorescein can be a useful diagnostic tool to determine the seriousness of the corneal lesions. Since organic material increases the concentration of combined Chlorine, and this study demonstrated that corneal lesions are most severely affected by combined chlorine, it is recommended to decrease the organic material in the water and to use an alternative for Chlorine, such as a biological filter.