Final answer:
The innermost layer of the eye, or the tunica interna, is comprised of the retina, which is a complex structure responsible for photoreception and visual processing. The retina does not include melanocytes or the start of the optic nerve; the choroid tissue in the vascular tunic contains the blood vessels that supply the retina.
Step-by-step explanation:
The inner layer (tunica interna) of the eye consists of the retina. The retina is part of the neural tunic and includes a complex arrangement of photoreceptor cells responsible for converting light into electrical signals, which the brain interprets as vision. This layer contains the nervous tissue involved in photoreception and has several sublayers including the ones housing the photoreceptor cells and their connecting synapses.
The retina is crucial for visual acuity as it processes light through its various cells including rods and cones, the bipolar cells, and the ganglion cells, before transmitting the information to the brain via the optic nerve. The fovea is the exact center of the retina, which is the area of sharpest vision.
While the retina contains a network of blood vessels that supply the eye with nutrients and oxygen, it does not house the start of the optic nerve, nor does it contain numerous melanocytes; those are found in the other layers of the eye. The choroid, part of the vascular tunic, is the highly vascular layer that provides blood supply to the outer retina and contains numerous capillaries.