A simple example

Consider the following example to get a feeling for the latency problem. Let $d$ be the density of the display in pixels per degree. Let $\omega$ be the angular velocity of the head in degrees per second. Let $\ell$ be the latency in seconds. Due to latency $\ell$ and angular velocity $\omega$, the image is shifted by $d \omega \ell$ pixels. For example, if $d = 40$ pixels per degree, $\omega = 50$ degrees per second, and $\ell = 0.02$ seconds, then the image is incorrectly displaced by $d \omega \ell = 4$ pixels. An extremely fast head turn might be at $300$ degrees per second, which would result in a $24$-pixel error.