A neural effect of partial visual deprivation in humans.
Certain human subjects have considerable sensitivity differences in the visual resolution of vertical gratings as compared to horizontal gratings. Although only subjects with pronounced ocular astigmatism exhibit this effect, the differences are of neural, rather than optical, origin. It is argued that the resolution anisotropies result from early abnormal visual input caused by astigmatism. This abnormal input permanently modifies the brain.
D001251:Astigmatism / Q000503:physiopathology*; D005556:Form Perception; D006801:Humans; D012029:Refraction, Ocular; D014795:Visual Pathways / Q000503:physiopathology*