Choroid Choroid The choroid, also known as the choroidea or choroid coat, is the vascular layer of the eye, containing connective tissues, and lying between the retina and the sclera. The human choroid is thickest at the far extreme rear of the eye (at 0.2 mm), while in the outlying areas it narrows to 0.1 mm. The choroid provides oxygen and nourishment to the outer layers of the retina. Along with the ciliary body and iris, the choroid forms the uveal tract. The structure of the choroid is generally divided into four layers (classified in order of furthest away from the
Anterior ciliary arteries arteries each, while the lateral rectus only receives one branch. Anterior ciliary arteries The anterior ciliary arteries are seven small arteries in each eye-socket that supply the conjunctiva, sclera and the rectus muscles. They are derived from the muscular branches of the ophthalmic artery. The anterior ciliary arteries are branches of the ophthalmic artery and run to the front of the eyeball in company with the extraocular muscles. They form a vascular zone beneath the conjunctiva, and then pierce the sclera a short distance from the cornea and end in the circulus arteriosus major. Three of the four rectus muscles;