Early eye development in vertebrates

This review provides a synthesis that combines data from classical experime ntation and recent advances in our understanding of early eye development. Emphasis is placed on the events that underlie and direct neural retina for mation and lens induction. Understanding these events represents a longstan ding problem in developmental biology. Early interest can be attributed to the curiosity generated by the relatively frequent occurrence of disorders such as cyclopia and anophthalmia, in which dramatic changes in eye develop ment are readily observed. However, it was the advent of experimental embry ology at the turn of the century that transformed curiosity into active inv estigation. Pioneered by investigators such as Spemann and Adelmann, these embryological manipulations have left a profound legacy. Questions about ea rly eye development first addressed using tissue manipulations remain topic al as we try to understand the molecular basis of this process.