What causes increased pressure in the eye?
The normal eye maintains its spherical shape (like an inflated balloon) by means of a watery fluid, called the aqueous humor, which is constantly secreted within the eye. As this fluid slowly drains out of the eye and into the blood stream through small channels in the wall of the eye, the eye pressure is maintained at a constant, normal level. In contrast, tears are produced by glands around the eye and are totally different than the aqueous humor inside the eye. If the aqueous drainage channels are blocked so that aqueous fluid is trapped inside the eye, then the pressure may build up to dangerous levels. Because the eye is a closed structure, this elevated eye pressure will push and damage the weakest part of the eye where the optic nerve fibers leave the eye at the optic disc. Loss of these nerve fibers causes “cupping” of the optic nerve. Cupping is one of the earliest signs of glaucoma. Glaucoma is not just one disease, but a group of diseases that all involve optic nerve damage.
