"Parallel-viewing can relax your overworked eye muscles. Alternating between parallel-viewing and cross-viewing can be a callisthenic work-out for the eyes. It can loosen up tight, overstressed eye muscles."
With the parallel viewing method the lines of sight of your eyes move outward toward parallel and meet in the distance at a point well behind and beyond the image. That's why it's called parallel viewing. When you parallel-view, the muscles inside your eye that control the focusing lens relax and lengthen.
Parallel viewing gallery