Foveal sparing. New anatomical evidence for bilateral representation of the central retina.

The pattern of retinal ganglion cell projections to the dorsal lateral geniculate nuclei has been demonstrated with horseradish peroxidase neuronography. A 1 degree-wide strip centered on the vertical meridian has been found in which ipsilaterally and contralaterally projecting ganglion cells intermingle. This strip expands to a width of 3 degrees at the fovea, since mixing of horseradish peroxidase-labeled and unlabeled ganglion cells was found in a band approximately 0.5 degrees wide along both the nasal and temporal rims of the foveola. These labeled ganglion cells rimming the foveal pit in its entirety represent a possible anatomical basis for "foveal sparing".