Computer User Preference
What computer users prefer agrees with the physiological findings.
In the Jaschinski-Kruza (1988) study mentioned earlier, all subjects judged an eye to screen distance of 20 inches as being too close, and all accepted a 40-inch distance.
Hill and Kroemer (1986) found that the closer the object, the lower the preferred viewing angle.
With a target 40 inches away, the preferred viewing angle was -30 degrees below the Frankfurt Plane (the Frankfurt Plane is an imaginary reference plane passing from the center of the ear hole through the bottom of the eyeball socket. When the head tilts forward, the Frankfurt Plane tilts with it).
At 20 inches, the downward preference increased to -38 degrees. With a normal computer-work posture, the average preferred viewing angle was -29 degrees below the Frankfurt Plane.
The subjects were not permitted to move their heads during these tests, so the Downward Gaze™ resulted solely from movement of their eyes.