This is for internal use only. Use opiClose() with
these Arguments and you will get the Value back.
A list with elements
err, which is an error code, NULL for no error
fixations, which is a matrix one row per fixation and three columns:
time (same as time_hw in opiPresent)
x (degrees relative to the centre of the image returned by opiInitialise - not the PRL)
y (as for x)