The pathogenesis of glaucomatous damage involves activation of astrocytes and involvement of oxidative stress in the mitochondria, which are located numerously in the axons of the optic nerve head (ONH). Astrocytes are activated by both mechanical and ischaemic stress. The major cause of oxidative stress is unstable blood flow, which is unstable if either intraocular pressure (IOP) fluctuates on a high level, exceeding the capacity for autoregulation from time to time, or if autoregulation by itself is disturbed. The main cause of disturbed autoregulation is primary vascular dysregulation syndrome. The simultaneous production of superoxide anions and nitric oxide leads to the damaging peroxinitrite, which induces apoptosis. Simultaneously, the entire microenvironment is changed, including an upregulation of matrix metalloproteinases (MMPs), contributing to tissue remodelling and thereby to excavation.

Three different systems can be used to grade the amount of glaucomatous damage when examining the field of vision,
Does disc evaluation help determining the amount of glaucoma damage ?
Should we depend on field examination or disc examination ?