Which cell type is primarily present at the optic disc and replaces the Muller cell footplates that form the ILM elsewhere?

Which cell type is primarily present at the optic disc and replaces the Muller cell footplates that form the ILM elsewhere?

• A. Astrocytes
• B. Müller cells
• C. Microglia
• D. Ganglion cells

Answer: (A)

The optic disc is surrounded by a glial environment dominated by astrocytes, which take over the role of forming the boundary there. In the rest of the retina, the inner limiting membrane is built by the endfeet of Müller cells, but at the optic nerve head those Müller endfeet are not present. Instead, astrocyte processes fill the region and create theILM-like border as retinal nerve fibers converge to form the optic nerve. Microglia and ganglion cells don’t form this boundary pattern; microglia are immune cells, and ganglion cells are neurons, not structural components of the ILM.

The optic disc is surrounded by a glial environment dominated by astrocytes, which take over the role of forming the boundary there. In the rest of the retina, the inner limiting membrane is built by the endfeet of Müller cells, but at the optic nerve head those Müller endfeet are not present. Instead, astrocyte processes fill the region and create theILM-like border as retinal nerve fibers converge to form the optic nerve. Microglia and ganglion cells don’t form this boundary pattern; microglia are immune cells, and ganglion cells are neurons, not structural components of the ILM.