FIGURE 1.

Summary of hypothesized scenarios of RGC degeneration. A vast number of extrinsic and intrinsic cues have been reported to trigger RGC degeneration. Increased IOP in glaucoma may induce mechanical stress at the optic nerve head leading to hypoxia and axonal transport defect. Inherited optic neuropathies often involve directly or indirectly mitochondrial defect. In all RGC disorders, glial cells are suspected to contribute to RGC degeneration. IOP, intraocular pressure; HIF, hypoxia inducible factor; ROS, reactive oxygen species; mtDNA, mitochondrial DNA; GluR, glutamate receptor.