Role of Brain-Derived Neurotrophic Factor for the Treatment of Glaucoma and Retinitis Pigmentosa

Primary open-angle glaucoma (POAG) is the most common form of glau co ma, representing up to 90% of cases. POAG is described as a multifactorial optic neuropathy that is chronic and progressive with a characteristic ac quired loss of optic nerve fibres. This loss develops in the presence of open anterior chamber angles, characteristic visual field abnormalities, and in creased intraocular pressure (IOP). POAG manifests by cupping and atrophy of the optic disc, in the absence of other known causes of glauco ma tous disease [1,2]. The exact cause of glaucomatous optic neuropathy is not known, although many risk factors have been identified, including the follo wing: elevated IOP, family history, race, age older than 40 years and myo pia. Elevated IOP is the most studied of these risk factors because it is the main clinically treatable risk factor for glaucoma and may cause neuro pathy via vascular dysfunction causing ischemia to the optic nerve or cribriform plate compression of the axons. Other factors may include excitotoxic damage from excessive retinal glutamate, deprivation of neuro nal growth factors, peroxynitrite toxicity from increased nitric oxide syn thase activity, im mune-mediated nerve damage and oxidative stress. The exact role that IOP plays in combination with these other factors and their significance to the initiation and progression of subsequent glaucomatous neuronal damage and cell death over time is still under debate [3,4].