Dendrite Degeneration in Glaucoma

Glaucoma is a group of slowly progressive neurodegenerative optic neuropathies in which the final common pathway is death of the retinal ganglion cells (RGCs) that comprise the optic nerve. While many risk factors have been identified, including intraocular pressure, the mechanistic pathway between the initial insult and RGC loss is still not clearly delineated. One paradigm is that of compartmentalized neurodegeneration, in which the axons, dendrites, and synapses undergo independent degenerative programs prior to cell soma loss. This chapter will focus on the features of dendritic remodeling in glaucoma and the implications on RGC function. Mounting evidence from various animal models of glaucoma demonstrates that changes in dendritic architecture precede cell death, although the detailed mechanisms and consequences of these morphologic and functional alterations have yet to be fully dissected. Such early dendritic alterations and synaptic rearrangements influence the normal function and structure of RGCs, thus giving important insight into the mechanism of circuit disassembly. At the same time, imaging of early dendritic alterations and identification of specific features of visual function that are first impaired represent promising new approaches to earlier diagnosis of this disease and improved disease progression recognition in humans.