A disease process that causes deterioration to the optic nerve fibers
resulting in visual loss. The causes of glaucoma are numerous, most commonly
due to elevated fluid pressure inside the eye. Damage that occurs due
to sudden rise of pressure is known as “acute” glaucoma. More
often, however, damage to the optic nerve occurs when fluid pressure is
higher than normal over a long period of time. This is called chronic
glaucoma and is generally silent and painless. (See FAQ’s on glaucoma
for more details.)