Specifically the LGN receives over 90% of the output of the retina in most primates (Perry et al. 1984). The LGN relays visual information to the V1.
Source: Perry, V.H., Oehler, R. and Cowey, A. (1984) ‘Retinal ganglion cells that project to the dorsal lateral geniculate nucleus in the macaque monkey’, Neuroscience, 12(4), pp. 1101–1123. Available at: https://doi.org/10.1016/0306-4522(84)90006-x.