Humans perceive and act within a visual world. This has become important even in

disciplines which are prima facie not concerned with vision and eye tracking is now used

in a broad range of domains. However, the world we are in is not two-dimensional, as

many experiments may convince us to believe. It is convenient to use stimuli in 2D or

21/2D and in most cases absolutely appropriate; but it is often technically motivated and

not scientifically.

To overcome these technical limitations we contribute results of an evaluation of different

approaches to calculate the depth of a fixation based on the divergence of the eyes

by testing them on different devices and within real and virtual scenarios.