Editing Choroid (section)

== Blood supply ==
There are two circulations of the eye:  the retinal (in the retina) and [[uvea]]l, supplied in humans by [[Ciliary arteries|posterior ciliary arteries]], originating from the [[ophthalmic artery]] (a branch of the [[internal carotid artery]]).<ref>[https://www.ncbi.nlm.nih.gov/books/NBK53329/ The Ocular Circulation]</ref>  The arteries of the [[uvea]]l circulation, supplying the [[uvea]] and outer and middle layers of the retina, are branches of the ophthalmic artery and enter the eyeball without passing with the optic nerve.  The retinal circulation, on the other hand, derives its circulation from the central retinal artery, also a branch of the ophthalmic artery, but passing in conjunction with the optic nerve.<ref name="eb">"Sensory Reception:  Human Vision: Structure and function of the Human Eye" vol. 27, p. 174  Encyclopædia Britannica,  1987</ref>  They branch in a segmental distribution to end arterioles and not [[anastomoses]]. This is clinically significant for diseases affecting  choroidal blood supply. The [[macula]] responsible for central vision and  the anterior part of the [[optic nerve]] are dependent on choroidal blood supply.<ref>{{cite journal | doi = 10.1136/bjo.59.11.631 | last1 = Hayreh | first1 = SS. |name-list-style=vanc |date=November 1975 | title = Segmental nature of the choroidal vasculature | journal = Br J Ophthalmol | volume = 59 | issue = 11| pages = 631–648 | pmid = 812547 | pmc = 1017426 }}</ref> The structure of choroidal vessels can be revealed by [[optical coherence tomography]], and blood flow can be revealed by [[Indocyanine green angiography]], and [[laser Doppler imaging]].<ref>Puyo, Léo, Michel Paques, Mathias Fink, José-Alain Sahel, and Michael Atlan. "Choroidal vasculature imaging with laser Doppler holography." Biomedical optics express 10, no. 2 (2019): 995–1012.</ref>

[[File:LDHvsICG.jpg|thumb| left|400px|Choroidal blood flow revealed with ICG-angiography (Spectralis, Heidelberg) and [[laser Doppler imaging]]<ref>Léo Puyo, Michel Paques, and Michael Atlan, "Spatio-temporal filtering in laser Doppler holography for retinal blood flow imaging," Biomed. Opt. Express 11, 3274–3287 (2020)</ref>]]

===In bony fish===
[[Teleosts]] bear a body of capillaries adjacent to the optic nerve called the choroidal gland. Though its function is not known, it is believed to be a supplemental oxygen carrier.<ref>"Eye (Vertebrate)" McGraw-Hill Encyclopedia of Science and Technology, vol. 6, 2007.</ref>