A gaze opacity map is a map used for web eye tracking studies and showing page areas where gaze has focused for a sample of visits.
A gaze opacity map has the same goals that a classic heatmap but it offers more detailed and clear results. It is often considered as the reverse of a heat map because only areas that got attention are shown and other areas are masked or blacked out. On a classic eye tracking heatmap, it is the opposite, attention areas are masked by hot colors and ignored areas are clearly observable.
See also gaze plot definition.
Some examples of gaze opacity maps:
image credit: Heatmaps2Go