What Triggers This Glaucoma Eye Disease?
Glaucoma is a disorder that affects about 40 million people in the world, blinding about 1 million to 2 million people in the United States. It is a slow, progressive disorder that ultimately causes irreversible blindness because it kills the nerves that pick up optical signals in the eye and carry them to the brain.
It is characterized by selective losses - areas are "punched out" or "drop out" of the visual field - rather than overall dimness.
The disease has been known since the time of Hippocrates, and for decades has been treated with partial success. The traditional theory of how glaucoma works has been that the amount of fluid inside the eye, the vitreous humor, increases steadily because of malfunctions either in glands that overproduce the fluid or in the meshwork of cells that drains the excess fluid from the eye.
What Characterizes Glaucoma? Glaucoma is mostly diagnosed by the very high pressures that build up as fluids accumulate inside the eye. Therapies have included many methods of draining the fluid and drugs to prevent glands from producing too much fluid. Hints from past research suggested that one neurotransmitter, glutamate, which excites the nerve cells' use during vision, had the potential to be toxic to its own cells at times, and in fact could produce death in optic cells that closely resembled the cell death in glaucoma. The disease may well begin with increased fluid in the eye. But the next step may be that the higher pressure crushes a few of the nerve cells in the retina. Inside the cells is a much higher concentration of glutamate, which then leaks out and poisons surrounding cells. Because glutamate is a neurotransmitter which turns nerve cells on, and gets them firing more rapidly, it literally can stimulate nerve cells to death when too much is present.
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