originating from the posterior chamber, the fluid (aqueous humor) passes between the iris and the lens and through the pupil, towards the anterior chamber, continuing toward the filtering elements of the trabecular meshwork, and into Schlemm canal, where it is conducted by way of small collector channels and larger aqueous veins into the venous system; normal production and outflow of aqueous humor account for the maintenance of the shape of the anterior chamber; impairment of the drainage system at the outflow channels leads to a rise in intraocular pressure, and is the most common cause of glaucoma.