Morphology and Function of the Salamander Eye

Abstract

The eye of most salamanders has a large cornea and a large lens. There are differences between eyes of permanently or predominantly aquatic salamanders, on the one hand, and of predominantly or fully terrestrial salamanders on the other. In water, there is no refraction of light at the corneal surface, since cornea and external medium are of the same refractive index. Focusing of an image onto the retina is achieved by the lens only. Therefore, predominantly aquatic salamanders show more or less spherical lenses and rather flat corneae. In air, the situation is quite different. Because of the low refractive index of the outer medium, in terrestrial salamanders the cornea becomes an important part of the dioptric system and the lens tends to be more flattened.