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. 2020 Jun 16;8:452. doi: 10.3389/fcell.2020.00452

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Copyright © 2020 Wareham and Calkins.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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Blood flow autoregulation in the eye. (A) A schematic showing an autoregulation curve that describes the relationship between normalized blood flow (y-axis) and perfusion pressure (x-axis). Autoregulation can only operate within a critical range of OPP and once OPP surpasses the optimal range (shown in pink), autoregulatory systems start to break down. (B) The two important vasoactive substances released by endothelial cells are nitric oxide (NO) and endothelin-1 (ET-1) and autoregulation of the vascular system in the eye relies on a delicate balance between the two; NO is a potent vasodilator released by smooth muscle cells and endothelial cells which acts via pericytes to dilate capillaries. Opposite in function is ET-1, a potent vasoconstrictor.