For NRV/PRV, which statement correctly describes the planes of accommodation and vergence?

For NRV/PRV, which statement correctly describes the planes of accommodation and vergence?

• A. The plane of accommodation moves with the demand and the plane of vergence moves
• B. The plane of accommodation moves with the demand and the plane of vergence moves with the demand
• C. The plane of vergence moves with the demand while the plane of accommodation remains fixed at the true target location
• D. Neither plane moves

Answer: (C)

The main idea is that near-view responses separate the alignment of the eyes from the focusing of the lens. When you look at a nearer object, the demand for convergence increases and the vergence system adjusts the eye angles to bring the object onto both foveas. That plane of vergence therefore moves with the demand. The focusing system, however, is driven by the actual distance to the target and the blur feedback it provides, so it stays fixed at the true target location unless the target itself changes distance. In NRV/PRV, this means the vergence changes with demand while accommodation remains tied to where the target really is.

The main idea is that near-view responses separate the alignment of the eyes from the focusing of the lens. When you look at a nearer object, the demand for convergence increases and the vergence system adjusts the eye angles to bring the object onto both foveas. That plane of vergence therefore moves with the demand. The focusing system, however, is driven by the actual distance to the target and the blur feedback it provides, so it stays fixed at the true target location unless the target itself changes distance. In NRV/PRV, this means the vergence changes with demand while accommodation remains tied to where the target really is.