  Battery-constrained power consumption, compute limitations, and high frame
rate requirements in head-mounted displays present unique challenges in the
drive to present increasingly immersive and comfortable imagery in virtual
reality. However, humans are not equally sensitive to all regions of the visual
field, and perceptually-optimized rendering techniques are increasingly
utilized to address these bottlenecks. Many of these techniques are
gaze-contingent and often render reduced detail away from a user's fixation.
Such techniques are dependent on spatio-temporally-accurate gaze tracking and
can result in obvious visual artifacts when eye tracking is inaccurate. In this
work we present a gaze-contingent rendering technique which only requires
saccade detection, bypassing the need for highly-accurate eye tracking. In our
first experiment, we show that visual acuity is reduced for several hundred
milliseconds after a saccade. In our second experiment, we use these results to
reduce the rendered image resolution after saccades in a controlled
psychophysical setup, and find that observers cannot discriminate between
saccade-contingent reduced-resolution rendering and full-resolution rendering.
Finally, in our third experiment, we introduce a 90 pixels per degree headset
and validate our saccade-contingent rendering method under typical VR viewing
conditions.
