Strategies for optic nerve rescue and regeneration in glaucoma and other optic neuropathies

Glaucoma is the most common age-related optic nerve disease and also the most common neuropathy, affecting ∼60 million people worldwide in its most common forms. This figure is expected to rise to 80 million by 2020. Glaucoma is a neurodegenerative disease in which various triggers induce cascades of secondary events, which ultimately lead to apoptotic retinal ganglion cell (RGC) death. The main risk factor for glaucomatous nerve damage is raised pressure in the eye. Understanding the cascades mediating optic nerve damage enables the development of new, neuroprotective treatment strategies that might not only target the initial insult but also prevent or delay secondary neurodegeneration. Furthermore, neuroregeneration and repopulation of the visual pathway by stem or neural precursor cells is becoming possible. Increasing understanding of the pathways involved in directed axon growth and manipulation of stem and progenitor cells towards an RGC fate have facilitated first successes in animal models of glaucoma.