The fovea is an area roughly in the centre of the eye where your vision is at its best. Peripheral vision is the less accurate eyesight you have "around the ed

The fovea is an area roughly in the centre of the eye where your vision is at its best. Peripheral vision is the less accurate eyesight you have "around the edges" of your eyes. I assume he's talking about foveated and peripheral rendering, that is rendering things better if they are "being looked at" by a fovea which is therefore sharper than the periphery.