Comparison of peripheral and central retina
SSB IMAGE INDEX
These two sections through the peripheral and central regions of the retina are aligned at the pigmented epithelium (cuboidal cells with brownish color, near bottom). Note that the peripheral retina is not only much thinner but has many fewer cells (as indicated by the number of nuclei) both in the ganglion cell layer (the topmost layer of nuclei, containing relatively few ganglion cell nuclei) and in the inner nuclear layer (the middle layer of nuclei, containing bipolar cell nuclei). Density of receptor cells also varies regionally but less markedly so than for the integrative bipolar and ganglion cells.
The resolution of the retina (i.e., its ability to distinguish fine details of the image) is limited not so much by the absolute number of receptor cells as by the number of ganglion cell axons which pass image "pixels" along the optic nerve. Thus the resolution is much higher in the central retina, particularly in the macula, where the number of ganglion cells is much greater than in the peripheral retina.
More on layers of retina
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Last updated: 15 January 2007 / dgk