Size and distribution of ganglion cells in the human retina.

Three human retinae have been evaluated for size and distribution of ganglion cells from a study of whole-mount Nissl preparations. With the aid of a data processing program a number of statistical data on th distribution of cell sizes has been attained. The parafoveal region is occupied by small cells. The mean cell diameter increases up to 30 degrees to 40 degrees from the fovea and then decreases further into the periphery. Histograms show homogeneous cell sizes in central retina, but greater variations towards peripheral retina. As all histograms are of a unimodal shape, differentiation of cell groups is difficult. However, the majority of ganglion cells belong to the small to medium-sized cell class, while large cells, practically absent from parafoveal retina, are almost evenly distributed in peripheral retina. The significance of our results for the alpha-, beta-, gamma-cell classification in discussed.