Glaucoma is an optic neuropathy in which the optic nerve axons are damaged, resulting in death of retinal ganglion cells (RGCs). The primary region of damage is thought to be the optic nerve head (ONH), with the lateral geniculate nucleus (LGN) and optic radiations to the visual cortex being secondarily affected. Neurotrophin deprivation resulting from optic nerve injury is thought to cause RGCs to die by apoptosis by inhibition of cell survival pathways. However, disruption of retrograde axonal transport is not the only mechanism associated with optic nerve damage and RGC death, and thus, an additional mechanism of injury is likely to be involved in glaucomatous optic neuropathy.