**2. Retinal ganglion cell death**

The neurodegeneration seen in glaucoma is as an end result of apoptosis (programmed cell death) of the retinal ganglion cell (RGC). When the retinal ganglion cell dies, there is a degenerative change along the axon with the resulting clinical findings including thinning of the retinal nerve fiber layer (objectively measured by Optical Coherence Tomography, Heidelberg Retinal Tomography or GDx) and increased optic disc cupping. Retinal ganglion cell apoptosis results in visual field loss and ultimately loss of vision in glaucoma. There are several etiologies for retinal ganglion cell (RGC) death which occurs with and without elevated intraocular pressures.

Retinal ganglion cell apoptosis is thought to be a result of several factors:


The glutamate and nitric oxide (NO) theories were the early proposed mechanisms for neurodegeneration. There is a proposed oxidative component which results in oxidative stress on the RGC due to increased IOP and hypoxia leading to apoptosis.
