This exhibit depicts the cross sectional anatomy of a normal eye and an eye with open angle glaucoma. Normally, aqueous fluid flows from the posterior chamber of the eye into the anterior chamber, through the pupil, and over the iris to drain into the trabecular meshwork. Open angle glaucoma occurs when a blockage occurs in the trabecular meshwork and aqueous fluid cannot be drained. Intraocular pressure increases, restricting blood flow, compressing the retina, and "cupping" the optic nerve outward. This decreases visual acuity, and if left untreated, can ultimately lead to blindness.