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
Highlights
-
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.