2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part IV: Biochemistry and Metabolism
Chapter 11: Vitreous
Ions and organic solutes in the vitreous originate from adjacent ocular tissues and blood plasma. The barriers that control their entry into the vitreous include the following:
vascular endothelium of iris vessels
nonpigmented epithelium of the ciliary body
inner wall endothelium of the Schlemm canal
vascular endothelium of retinal vessels
retinal pigment epithelium (RPE)
Together, these structures constitute the blood–ocular barrier. The concentrations of sodium (Na+) and chloride (Cl−) in the vitreous are similar to those in plasma, but the concentration of potassium (K+) is higher than that in plasma, as is that of ascorbate.
Bishop PN. Structural macromolecules and supramolecular organisation of the vitreous gel. Prog Retin Eye Res. 2000;19(3):323–344.
Mayne R, Brewton RG, Ren Z-X. Vitreous body and zonular apparatus. In: Harding JJ, ed. Biochemistry of the Eye. London: Chapman & Hall Medical; 1997:135–143.
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.