The visual field test checks the central area of vision for "blind spots".  The area tested depends on viewing distance and screen size, but is of the order of 15 degrees. 

The program employs a multiple-stimulus screening approach (see McClure 1988), but no attempt is made to determine individual thresholds or to record the position or depth of any blind spots.

 The final score is based on the number of stimuli missed.  A score of less than 50% indicates that there may be a significant field loss and the user should have a full eye examination.  However it may indicate that there are considerable reflections on the screen.  The Administrator should ensure that a subsequent test is performed under ideal conditions.

See the Amsler Grid as an alternate to this test.