2020–2021 BCSC Basic and Clinical Science Course™
2 Fundamentals and Principles of Ophthalmology
Part IV: Biochemistry and Metabolism
Chapter 12: Retina
The retina has the highest rate of oxygen consumption of any tissue in the human body because of its high metabolic activity.
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.
Light induces hyperpolarization, leading to a cascade of reactions in the photoreceptor outer segments called phototransduction, which converts light energy into an electrical impulse.
Rods are highly sensitive and can be stimulated by a single photon, whereas cone photoreceptors can adapt to a wider range of light intensities.
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.