Figure 3. The regenerated retina is able to form an optic nerve. Intact eyes (A, D) and eyes 30 days postretinectomy exposed to either an FGF-2 bead (B, E) or a control bead (C, F) were injected with DiI to label cell membranes. Ten days later, the ganglion cell axons could be seen projecting through the optic nerve in both intact and FGF-2 exposed eyes (D and E). Control retinectomized eyes did not regenerate a retina and therefore did not project their axons through what remained of the optic nerve (F). D, E, and F correspond to fluorescent views (DiI labeling) of the bright-field images shown in A, B, and C respectively. Abbreviations: eyeball (E); optic nerve (ON).