2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part IV: Biochemistry and Metabolism
Chapter 11: Vitreous
Composition
Low-Molecular-Weight Solutes
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:
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vascular endothelium of iris vessels
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nonpigmented epithelium of the ciliary body
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inner wall endothelium of the Schlemm canal
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vascular endothelium of retinal vessels
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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.
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Bishop PN. Structural macromolecules and supramolecular organisation of the vitreous gel. Prog Retin Eye Res. 2000;19(3):323–344.
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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.