Globe: Choroid

The choroid, the third part of the vascular tunic or uvea, lies between the sclera and the retina and consists of three layers. From outer to inner, these layers are: a stroma of loose connective tissue with many blood vessels and melanocytes; the choriocapillary layer, a capillary layer that supplies the retina; and Bruch’s membrane that is shared with the retina. 100x, 400x

The choroid, the third part of the vascular tunic or uvea, lies between the sclera and the retina and consists of three layers. From outer to inner, these layers are: a stroma of loose connective tissue with many blood vessels and melanocytes; the choriocapillary layer, a capillary layer that supplies the retina; and Bruch’s membrane that is shared with the retina. 100x, 400x

The choroidal stroma consists of a loose connective tissue containing large melanocytes and vessels of varying sizes.

The choroidal stroma consists of a loose connective tissue containing large melanocytes and vessels of varying sizes.”

The choriocapillary layer consists of fenestrated capillaries that supply the pigment epithelium and the outer layers of the retina.  The basal laminae of these capillaries form the outermost layer of Bruch’s membrane.

Bruch’s membrane forms the interface between the choroid and the retina and insures proximity of a vascular supply to the pigment epithelium of the retina. From inner to outer, Bruch’s membrane consists of the basal lamina of the pigment epithelium of the retina, a layer of collagenous and elastic fibers, and the basal lamina of the choriocapillary endothelial cells.

The retina, the innermost tunic and light sensing part of the eye, consists of a nonvisual portion (a pigmented epithelium) and a visual portion (a multilayered outgrowth from the brain).