2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part IV: Biochemistry and Metabolism
Chapter 9: Aqueous Humor, Iris, and Ciliary Body
Aqueous humor is secreted by the nonpigmented ciliary epithelium (NPE) from a substrate of blood plasma.
Aqueous humor is distinct from plasma, as it has low protein content and a high concentration of ascorbate.
Ascorbate has antioxidant properties, and its high concentration in the aqueous protects intraocular structures by blocking ultraviolet (UV) light.
The blood–aqueous barrier is composed of the tight junctions of the NPE, the iris vasculature, and the inner wall endothelium of the Schlemm canal.
Disruption of the blood–aqueous barrier allows mixing of blood contents with ocular fluids, producing a plasmoid aqueous, as occurs in anterior uveitis.
Excerpted from BCSC 2020-2021 series: Section 2 - Fundamentals and Principles of Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.