Which retinal layer contains the axons of retinal ganglion cells?

• A. Nerve fiber layer
• B. Inner nuclear layer
• C. Inner plexiform layer
• D. Ganglion cell layer

Answer: (A)

The nerve fiber layer is where the axons of retinal ganglion cells run toward the optic nerve. Each ganglion cell has its cell body in the ganglion cell layer, and its axon extends into the nerve fiber layer as it heads toward the optic disc. Inside the retina these axons are unmyelinated; they only become myelinated once they pass through the lamina cribrosa to form the optic nerve. The other layers have different roles: the inner nuclear layer contains the cell bodies of bipolar, amacrine, and horizontal cells; the inner plexiform layer is where synapses between bipolar/amacrine cells and ganglion cells occur; and the ganglion cell layer houses the ganglion cell bodies.