Anatomy Overview

What are the layers of the choroid and their associated characteristics?

  • Choroid: the posterior segment of the uvea, providing blood supply to the outer retina.

  • Composed of 5 layers:

    • Bruch's membrane: Separates the retinal pigment epithelium from the choroid.

    • Choriocapillaris: Dense network of fenestrated capillaries, creating high oncotic pressure that drives fluid from retina to choroid.

    • Sattler's layer: Medium-sized arteries and arterioles.

    • Haller's layer: Large blood vessels.

    • Suprachoroid: Transition zone between choroid and sclera.

What are the layers of the retina and the cells within them?

Innermost

  • Inner Limiting Membrane (ILM): Separates the retina from the vitreous.

  • Nerve Fiber Layer: Composed of the axons of retinal ganglion cells. This layer’s basal lamina is the ILM.

  • Ganglion Cell Layer: Cell bodies of ganglion cells.

  • Inner Plexiform Layer: Bipolar cell axons synapse with ganglion cells. It also includes synapses from amacrine cell dendrites to modulate electrical conduction between bipolar and ganglion cells.

  • Inner Nuclear Layer: Cell bodies of bipolar cells, horizontal cells, and amacrine cells.

    • Bipolar cells transmit synaptic inputs from photoreceptor cells to ganglion cells.

    • Horizontal cells modulate signals from rods and cones.

  • Outer Plexiform Layer: Axons of photoreceptor cells synapse with cells within the inner nuclear layer.

  • Outer Nuclear Layer: Cell bodies of both rods and cones.

  • External Limiting Membrane: Separates cell bodies of rods and cones from their inner and outer segments.

    Outermost