Ocular Abnormalities in Carp Chronically Exposed to Various Surfactants

Ocular abnormalities in cazp exposed to the surfactants, laurylbenzene sulfonate(10 ppm, 20ppm) and sodium stearate (10ppm, 50ppm) were investigated. Exposure to the two kinds of surfactants produced almost similar symptoms in the ocular fundus of the carp. The initial abnormality was dilation of the hyaloid vessels. This dilation can be regarded as an early sign of disturbance in the external environment. The final sign was narrowing of these vessels. Normal hyaloid vessels become dilated as a result of even slight anoxia. However, the narrowing of hyaloid vessels affected by the surfactants never become dilated under the same anoxic conditions. In some carp, wide spreading white patches and pigmented patches were observed in the fundus. From these observations, it was considered that some degeneration occurred in the hyaloid vessels. These abnormalities of the retina may be the result of a functional disorder of the peripheral cir-culatory system. Using our ophthalmoscopic method, we were able to clearly follow the transi- tion of a morbid state in fish to some extent. This method is considered to be suitable for practical use in the clinical examination of fishes.