The glaucomas are a family of diseases, having in common a progressive
loss of the retinal ganglion cells (RGCs) whose axons comprise the optic nerve.
While elevated IOP is the most common risk factor for developing glaucomatous
optic neuropathy, IOP reduction is not always an effective therapy. In some cases, progressive visual field
loss occurs in patients with “normal” IOP. To better diagnose and more
comprehensively treat glaucoma, it is important to elucidate the underlying
pathophysiological mechanisms including the possible contributions by
neurotrophin deprivation, glutamate excitotoxicity, oxidative stress, nitric
oxide or impaired microcirculation.