2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part IV: Biochemistry and Metabolism
Chapter 12: Retina
Highlights
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The retina has the highest rate of oxygen consumption of any tissue in the human body because of its high metabolic activity.
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Retinal neurons (photoreceptor, bipolar, horizontal, amacrine, and ganglion cells), glial cells (Müller cells, astrocytes, and microglia), and vascular cells (endothelial cells and pericytes) together form a functional neurovascular unit that converts light into a neural signal.
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Light induces hyperpolarization, leading to a cascade of reactions in the photoreceptor outer segments called phototransduction, which converts light energy into an electrical impulse.
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Rods are highly sensitive and can be stimulated by a single photon, whereas cone photoreceptors can adapt to a wider range of light intensities.
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Gene mutations affecting components of the phototransduction pathway lead to inherited retinal dystrophies with varying clinical phenotypes.
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.