Psychophysical localization of the human visual streak

In a topographical study of the human retina, Curcio and Allen documented the presence of the human visual streak, which they described as a prominent nasotemporal asymmetry in ganglion cell density. This asymmetry could also be expected to be measurable in any visual function limited by ganglion cell density. By using an interferometer we sought to test the hypothesis of Thibos et al. that peripheral resolution acuity is limited by the spacing of ganglion cells and should therefore reflect the anatomical asymmetry of the visual streak, once the attenuating effects of the eye's optics have been removed. This proved to be the case and differences predicted by a ganglion cell density of 2:1 were easily measurable. This study has potential clinical implications for the detection of disease or abnormalities of the visual system that cause death or dysfunction of retinal ganglion cells.