Innermost layer: the retina (nervous tunic)

• Optic disc
  • Formed by axons of ganglion cells that leave the eye to form the optic nerve
  • Located medially to the fovea centralis
  • Insensitive to light due to lack of photoreceptors (physiologic scotoma, i.e., blind spot)
  • Contains the optic cup
    • Central, cup-like depression in the optic disc
    • Site of transversing of retinal vessels
    • Point of exit for ganglion cell axons leaving the eye
• Macula
  • An oval-shaped yellow spot on the lateral side of the optic disc, near the center of the posterior wall of the retina
  • Lacks blood vessels
  • Contains the fovea centralis
    • A central depression in the macula (foveola)
    • Contains the highest density of cones, each of which is connected to a single ganglion cell
  • Point of sharpest vision (100% visual acuity)