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

The boundary between perifovea and parafovea is characterized 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 inner retina changes its thickness as you move from the perifovea toward the parafovea, and this is most evident in the ganglion cell layer. In the perifovea the ganglion cell layer is relatively thin, about two cell layers deep, because the foveal pit displaces many cells away from the center. As you transition into the parafovea, more ganglion cells accumulate, thickening the layer to about four cell layers. This four-layer thickness marks the boundary between perifovea and parafovea in NBEO anatomy descriptions, so four cell layers is the best descriptor for that transition.

The inner retina changes its thickness as you move from the perifovea toward the parafovea, and this is most evident in the ganglion cell layer. In the perifovea the ganglion cell layer is relatively thin, about two cell layers deep, because the foveal pit displaces many cells away from the center. As you transition into the parafovea, more ganglion cells accumulate, thickening the layer to about four cell layers. This four-layer thickness marks the boundary between perifovea and parafovea in NBEO anatomy descriptions, so four cell layers is the best descriptor for that transition.