What structure is formed by the axons of ganglion cells?

The structure formed by the axons of ganglion cells is the optic nerve. In the retina, when light is converted into electrical signals by photoreceptors, these signals are processed and transmitted through various layers, culminating in the ganglion cells, whose axons come together to form the optic nerve. This nerve carries visual information from the retina to the brain, where it is interpreted as vision. Therefore, the optic nerve plays a crucial role in the visual pathway and directly connects the eye to the brain, making it an essential structure for sight.

The other options do not relate to the axons of ganglion cells. The pinna is part of the outer ear, responsible for collecting sound waves. The cornea is a transparent layer covering the front of the eye, aiding in focus and protection. The lens of the eye helps to focus light onto the retina but is not constituted by the axons of ganglion cells. Therefore, in the context of the structures that involve the axons of ganglion cells, the optic nerve is the accurate and relevant answer.