Foveated rendering
Renders the centre of the image at full resolution and the periphery progressively coarser, since the eye only sees sharply in a small central spot anyway.
The retina's acuity is concentrated in the fovea, a tiny pit in the macula; just a couple of degrees out, vision is blurry. Foveated rendering exploits this by spending the GPU budget where the gaze actually is and economising on the rest — a close relative of level of detail (LOD), only driven by where the eye looks rather than by distance.
Fixed foveation assumes the gaze is centred; dynamic foveation follows the eye with a tracker, most common in VR headsets where every pixel is drawn twice (once per eye). Hardware support comes via variable-rate shading. The trick is making the transition imperceptible: drop the periphery too hard and the corner of the eye catches the shimmer at once, because peripheral vision is acutely sensitive to motion.