project light onto the retina. Meridians correspond to sections of great circles passing through the centre of the fovea. In an analogy to Meridian (geography), in which meridians are lines of longitude, the North pole might correspond to the fovea, Greenwich would correspond to a retinal location about 39 degrees to the left of the fovea (because the retinal image is inverted, this corresponds to a location in the visual field to the observer's right), and the South pole would correspond to the centre of the pupil. The meridian of the visual field has been found to influence the folding of the cerebral cortex. In both the V1 and V2 areas of macaques and humans the vertical meridian of their visual field tends to be represented on the cerebral cortex's convex gyri folds whereas the horizontal meridian is tends to be represented in their concave sulci folds. See also Angle of view Field of view Peripheral vision References IPS Perimetry Standards 1978. (2002). Author. Department of Ophthalmology & Visual Sciences, The University of Iowa. Retrieved March 4, 2005, from http://webeye.ophth.uiowa.edu/ips/GEN-INFO/standards/STANDARD.HTM Vision