There is a constant flow of fluid in the eyeball. This fluid, called intraocular, is made and then reabsorbed. One in one hundred individuals have a narrowing in the area of the eye located where intraocular fluid flows out. When this area suddenly closes off, it results in a build up of fluid pressure known as acute Glaucoma. Acute angle Glaucoma may be the primary disease, or it may occur secondary to another eye disease, such as Posterior Uveitis or lens dislocation.