Stages of Retinal Development
Text for the Stages of Retinal Development section is quoted or paraphrased from Rijli et al., 1993 
Stage IX (NF stages 35-37)
Retinal developmental stage IX marks the very first appearance of the protein in the cytoplasm of specific cells in the outer nuclear layer (ONL).
Stage X (NF stages 36-38)
At retinal stage X cone morphogenesis is more advanced, although the cell is still immature (Fig. 4A and 8). At this stage, ribbon synapses between photoreceptor and horizontal cells are first detected (Witkovsky and Chen, 1977).
Stage XI (NF stages 39-42)
Retinal developmental stage XI is a period of synaptogenesis and retinal response to light.
Stage XII (NF stages 43-50)
The onset of visual function occurs at retinal developmental stage XII. Cones and rods are morphologically distinguishable, and functionally mature.