If Blindspot fixation monitoring has been selected, the software will attempt to determine the location and size of the blindspot by presenting a series of single stimuli in the expected area of the blindspot.


The algorithm attempts to determine the horizontal and vertical extent of the blindspot and thus locate its centre.  


In single screen mode the patient is simply instructed to fixate as steadily as possible and press the space bar if they see a "dot flash". In dual screen mode, the process can be monitored as shown below.




If the blindspot cannot be located a warning message will be displayed and Blindspot fixation monitoring will be switched off for this eye.


If the blindspot is located successfully, a single stimulus is presented in the centre of the blindspot at random intervals throughout the test.  If the patient is fixating accurately, this stimulus will not be detected.  If however, the patient is not fixating correctly, the stimulus will fall outside the blindspot and will be detected.  This therefore provides an indication of how well the patient is fixating and is reported as Fixation losses /3 on the chart.