This is the drain inside the eye where excess aqueous fluid drains and returns back to the bloodstream. This drain is located in a 360-degree ring inside the eye, right where the sclera (the white of the eye) meets the iris (the colored part of the eye). The trabecular meshwork is difficult to see directly, even when using the eye microscope because it is located inside the eye and “around the corner” in the angle of the eye. To help with visualization, a special mirrored-lens can be placed on the surface of the eye. This technique is called gonioscopy and is painless. It is believed that people with chronic open angle glaucoma have something microscopic clogging up the meshwork (like a dirty coffee filter). Other people have narrow angles, such that their drainage angle is tight so that fluid has a hard time reaching the trabecular meshwork to begin with. If this narrow drainage angle closes off entirely, fluid can’t drain out of the eye and the ocular pressure shoots up very high. This process is called acute glaucoma, and a person’s risk for having a glaucoma attack can be estimated by examining the trabecular meshwork during gonioscopy.