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.