Ultraviolet Light: Photosensitivity and Other Effects on the Visual System *

It is generally stated in elementary lectures on sensory systems that the limits of the visible spectrum are 400 nm (violet) and 700 nm (red), although there are several exceptions to this generalization. Recently, the properties of ultraviolet (UV) vision in invertebrates, as well as vertebrates, have been better characterized, and it is worthwhile to examine visual phenomena in the UV region of the spectrum. The purpose of this review is to integrate what is known about UV vision in invertebrates, which have been particularly well studied, with a growing literature on UV sensitivity and UV effects in the visual systems of humans and other vertebrates.