Which Bruch's membrane layer lies closest to the choriocapillaris?

• A. Basement Membrane of the Choriocapillaris
• B. Outer Collagenous Layer
• C. Elastic Layer
• D. Inner Collagenous Layer

Answer: (A)

Bruch's membrane is organized in a specific sequence between the retinal pigment epithelium and the choroid, with five distinct layers from the retina toward the choroid: the RPE basement membrane, the outer collagenous layer, the elastic layer, the inner collagenous layer, and then the basement membrane of the choriocapillaris. The layer that sits directly next to the choriocapillaris is the basement membrane of the choriocapillaris, which is the basal lamina of the choriocapillaris endothelium. The other layers lie on the retinal side, separated from the choriocapillaris by these layers. This arrangement is important for how nutrients and waste diffuse between the choroid and retina and has implications in aging and diseases like AMD.