Development of the retina

Appreciating the mechanisms responsible for normal retinal development is critical to understanding disease processes affecting the pediatric retina. Remarkably, the retina develops over a relatively long period of time beginning from the early gestational period through the first years of life. Consider, for example, that the human macula, which although first evident at a gestational age of 11 weeks, is still very immature even at birth [1]. The relative long window of retinal development is a vulnerability leaving this intricate tissue susceptible to specific genetic and environmental insults over an extended period. Furthermore, many of the central concepts in developmental biology were first discovered, and continue to be uncovered by studies of retinal development in various systems ranging from drosophila to man. Thus, the study of retinal development continues to provide important insights not only into the pediatric retina, the main subject of this book, but also into the mysteries of developmental embryology, vertebrate evolution, and disease pathophysiology. The following pages are meant to provide a foundation to the subject rather than a compendium of genes and syndromes. The emphasis taken, therefore, is to encourage the reader to understand the origin of the current concepts that exist, most importantly to appreciate that we are only at the tip of the iceberg with most important discoveries and breakthroughs yet to be made.