Figure 1.

A model of primary and secondary insults in glaucoma and the involvement of low ocular perfusion pressure (OPP). The primary insult occurs at the optic nerve head owing to increased intraocular pressure (IOP) and optic nerve head (ONH) ischemia. Reduced cerebrospinal fluid (CSF) pressure and the biomechanical properties of ocular tissues modify susceptibility. In primary open angle glaucoma (POAG) retinal ganglion cells (RGCs) then function at reduced energy states with affected mitochondria. Oxidative stress due to reactive oxygen species (ROS) and secondary insults such as abnormal autoregulation of abnormal neurovascular coupling can lead to RGC death.