Figure 1.

The neurotrophic factor (NTF) deprivation theory in the adult visual system. (A) Under physiological conditions, NTFs are secreted by cells in target brain centers and retrogradely transported alongside the optic nerve towards the retinal ganglion cells (RGCs). (B) In situations where axonal transport is perturbed—as witnessed in glaucoma and other optic neuropathies—RGCs are deprived from target-derived NTFs. According to the NTF deprivation theory, this scarcity is the final push that forces the struggling RGCs to surrender to the injury stressors and undergo apoptosis.