Which retinal layer is not present in the fovea?

Which retinal layer is not present in the fovea?

• A. Retinal nerve fiber layer
• B. Internal limiting membrane
• C. Inner nuclear layer
• D. Outer nuclear layer

Answer: (A)

The fovea is a specialized pit in the retina where inner retinal layers are displaced away to allow dense packing and direct sampling by cone photoreceptors. Because those inner layers are moved aside at the center, the fibers from ganglion cells—the retinal nerve fiber layer—are not present there, eliminating a potential light obstacle and improving resolution. The boundary layer at the surface, the internal limiting membrane, remains intact, and the inner nuclear layer becomes very thin or displaced near the fovea, while the outer nuclear layer, rich with cone nuclei, remains—making the fovea cone-dominated. So the retinal nerve fiber layer is the layer not present at the very center of the fovea.

The fovea is a specialized pit in the retina where inner retinal layers are displaced away to allow dense packing and direct sampling by cone photoreceptors. Because those inner layers are moved aside at the center, the fibers from ganglion cells—the retinal nerve fiber layer—are not present there, eliminating a potential light obstacle and improving resolution. The boundary layer at the surface, the internal limiting membrane, remains intact, and the inner nuclear layer becomes very thin or displaced near the fovea, while the outer nuclear layer, rich with cone nuclei, remains—making the fovea cone-dominated. So the retinal nerve fiber layer is the layer not present at the very center of the fovea.