Figure 7. The optic cup lip is a common progenitor pool for retina and anterior eye. A: Model of optic cup subdivision into retinal and anterior compartments, based upon gene expression patterns and proliferation indices. The early optic cup would consist of an expansive retinal compartment (green) and separate anterior eye compartment (orange), situated at the peripheral optic cup. With development, the retina would grow through intrinsic expansion and the anterior structures, ciliary body and iris, would be exclusively derived from the optic cup lip. B: Permanent tagging of OCL cells reveals a substantial contribution from the OCL to the retina in addition to the anterior eye tissues. Intrinsic expansion of the inner layer of the early optic cup accounts for only a portion of retinal growth.