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
DecisionDx-UM of the eye which includes the iris, ciliary body, and choroid. Treatment for the primary eye tumor consists of eye-sparing therapy (plaque radiotherapy or proton beam irradiation) or eye removal (enucleation). Both are highly effective with ‘cure’ rates above 90%. However, as has been well documented in multiple publications including the Collaborative Ocular Melanoma Study (COMS), in nearly 50% of patients the melanoma has likely already metastasized by the time the primary eye tumor has been diagnosed and treated. The majority of these metastases are microscopic and clinically undetectable at the time of primary tumor diagnosis. Unfortunately, many of the