Why Do Nerve Cells Die?
Cells are factories. They need fuel, they make wastes, they need instruments to utilize the fuel and dispose of the wastes, and they must have structural integrity in order to survive. The ganglion cells of the retina need sugar and oxygen, but they also need nerve growth factors to sustain them. They can be killed by their own waste products, such as the acids that result from burning sugars and fats, the ammonias that result from using protein. A toxin of special interest in glaucoma is glutamate, a substance which is essential for cell functioning, but which in excess can cause the death of the cell. The wall of the cell must be intact, but must function to let in those things it wants and keep out those things it does not want. Calcium is needed for the heart to beat properly, for the bones to develop, but when the cell membrane breaks down and allows the calcium outside to get inside, the cell quickly dies. Some substances cause cells to become excited, and when present in excess,
