Mitochondria: Their role in ganglion cell death and survival in primary open angle glaucoma.

Retinal ganglion cell axons within the globe are functionally specialised being richly provided with many mitochondria. Mitochondria produce the high energy that is required for nerve conduction in the unmylenated part of the ganglion cell axons and for the maintenance of optimum neuronal function. We proposed that in the initiation of glaucoma (POAG) an alteration in the quality of blood flow dynamics in the optic nerve head results in sustained or intermittent ischemia of a defined nature. This results in normal mitochondrial function being negatively affected and as a consequence retinal ganglion cell function is compromised. Ganglion cells in this state are now susceptible to secondary insults which they would normally tolerate. One secondary insult to ganglion cell mitochondria in such a state might be light entering the eye. Other insults to the ganglion cells might come from substances such as glutamate, prostaglandins and nitric oxide released from astrocytes and microglia in the optic nerve head region. Such cascades of events initiated by ischemia to the optic nerve head region ultimately cause ganglion cells to die at different rates.