A binocular viewer, a method of measuring and training vision that uses a binocular viewer and a vision measurement and training system that employs a computer to control the binocular viewer. In one embodiment, the binocular viewer has left and right display elements and comprises: (1) a variable focal depth optical subsystem located in an optical path between the display elements and a user when the user uses the binocular viewer and (2) a control input coupled to the left and right display elements and the variable focal depth optical subsystem and configured to receive control signals operable to place images on the left and right display elements and vary a focal depth of the variable focal depth optical subsystem. In another embodiment, the binocular viewer lacks the variable focal depth optical subsystem, but the images include at least one feature unique to one of the left and right display elements.