Glaucoma is a leading cause of world blindness, and retinal ganglion cell death is its pathological hallmark. There is accumulating evidence that glaucomatous damage extends from retinal ganglion cells to vision centers in the brain. In an experimental primate model of unilateral glaucoma, degenerative changes are observed in magnocellular, parvocellular, and koniocellular pathways in the lateral geniculate nucleus, and these changes are presented in relation to intraocular pressure and the severity of optic nerve damage. Neuropathological findings are also present in lateral geniculate nucleus layers driven by the unaffected fellow eye. Finally, there is information on changes in the visual cortex in relation to varying degrees of retinal ganglion cell loss. The implications of these findings for refining concepts regarding the pathobiology of progression, and the detection and treatment of glaucoma, are discussed.