Which layer is the third in Bruch's membrane?

Which layer is the third in Bruch's membrane?

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

Answer: (B)

Bruch's membrane is organized into five layers in a line from the retina toward the choroid. Starting at the retina side, the sequence is: basement membrane of the RPE, inner collagenous layer, elastic layer, outer collagenous layer, then the basement membrane of the choriocapillaris. The third layer in this order is the elastic layer. This layer provides the membrane with its elastic properties and forms part of the permeability barrier between the RPE and the choroid. With aging, changes in the elastic layer (such as calcification and fragmentation) can alter diffusion and contribute to retinal pathologies.