Glaucoma is increased pressure within the eye (intraocular pressure = IOP). Cells inside the eye produce a clear fluid (“aqueous humor”) that maintains the shape of the eye and nourishes the tissues inside the eye. (Note: aqueous humor is NOT the same fluid as tears. Tears bathe the outside surface of the eye. Aqueous humor circulates inside the eye. These two fluids do not interact). The aqueous humor drains out of the eye into the bloodstream through the drainage angle–a sieve or meshwork-like area through which aqueous percolates out of the eye. The balance of aqueous fluid production (“the faucet”) and drainage (“the drain in the sink”) is responsible for maintaining normal pressure inside the eye. In glaucoma, the drain becomes partially or completely clogged but the “faucet” steadily keeps producing aqueous, causing pressure to build inside the eye. If untreated, this increased pressure usually causes irreversible blindness, in addition to stretching and enlargement of the eye.