Aqueous Humor and the Dynamics of Its Flow: Formation of Aqueous Humor

Abstract

Aqueous humor has numerous functions including optical transparency, structural integrity, and providing nutrition for the eye without the need for blood vessels that would be opaque. Ordinarily, no blood vessels are found in the cornea, lens, vitreous, or trabecular meshwork. Indeed, proportionately, the eye contains the largest avascular mass found in an organ anywhere in the body. The traditionally avascular structures of the eye including the cornea, lens, and trabecular meshwork require essential nutrients including glucose, oxygen, and amino acids to function properly. The aqueous humor not only provides these nutrients and removes harmful substances and byproducts of metabolism but also provides an optimally balanced pH and environment for these structures to function, including providing an optically clear media for vision. Aqueous humor also generates intraocular pressure to maintain the eye's structural integrity and the position of the refractive surfaces of the eye relative to each other. Furthermore, aqueous humor contains a relatively high concentration of ascorbate, which may offer protection from UV radiation by removing free radicals. Finally, the aqueous humor provides a crucial role in mediating the immune response in the eye by modulating its rate of formation and thus the concentration of immune mediators when fighting off infections. It is largely the energy available from the cellular metabolism of the epithelia of the ciliary processes that drives the extraction and formation of the aqueous humor.