From the retina to lateral geniculate nuclei (lgn) Visual information leaves the retinas through the optic nerves. Each of the million ganglion cells in each retina sends its axon out the back of the eye through the blind spot. The retina"s axons fibers form the 2 optic nerves. These optic nerves fall below the pituitary hence tumours under the pituitary gland can cause problems with the visual fields. Since the nasal fibers cross, all the information from the right hemifield comes together in the left cerebral hemisphere, and vice versa. The 2 nerve bundles emerging from the chiasm are the optic tracts. The optic tracts terminate in the 2 lateral geniculate nuclei (lgn) in the thalamus (which project mainly to primary visual cortex, v1) Together, the 2 lgn have ~ 2 million neurons. Each lgn has 6 layers each layer represents the contralateral visual hemifield.