The boundary between the perifovea and parafovea is defined by the ganglion cell layer thickness of how many cell layers?

The boundary between the perifovea and parafovea is defined by the ganglion cell layer thickness of how many cell layers?

• A. Two cell layers
• B. Three cell layers
• C. Four cell layers
• D. Five cell layers

Answer: (C)

The boundary between perifovea and parafovea is set by how thick the ganglion cell layer is in the inner retina. As you move from the fovea outward, the ganglion cell layer thickens, reaching about four cell layers in thickness at the transition from perifovea to parafovea. Inside the parafovea, the GCL remains around this thickness, reflecting higher ganglion cell density, while beyond that boundary toward the perifovea the layer thins again. This four-layer thickness serves as the histological marker for where parafovea ends and perifovea begins.

The boundary between perifovea and parafovea is set by how thick the ganglion cell layer is in the inner retina. As you move from the fovea outward, the ganglion cell layer thickens, reaching about four cell layers in thickness at the transition from perifovea to parafovea. Inside the parafovea, the GCL remains around this thickness, reflecting higher ganglion cell density, while beyond that boundary toward the perifovea the layer thins again. This four-layer thickness serves as the histological marker for where parafovea ends and perifovea begins.