DAMAGE TO THE RAINBOW-TROUT (ONCORHYNCUS-MYKISS) LENS FOLLOWING AN ACUTE DOSE OF UVB

Rainbow trout (Oncorhynchus mykiss) were used to model the solar radiation-induced cataract that occurs in hatchery-reared lake trout (Salvelinus namaycush). Rainbow trout eyes were exposed to wide-band predominantly UVB radiant energy from a filtered 1000W xenon source. Lenticular damage was assessed and classified and corneal damage noted. Lenticular theshold radiant exposure was 0.48 J.cm-2 which is in the same range as the mammalian lens. Permanent lenticular damage occurred at radiant exposure levels approximately twice the theshold for lenticular radiant exposure (also similar to the mammalian response). Slit-lamp and scanning electron microscopical results support the theory of post-exposure anterior subcapsular epithelial cell damage, lens fibre swelling, and eventual rupture, leading to areas of lower refractive index in the anterior subcapsular region of the lens.