A display subsystem for a virtual image generation system used by an end user, comprises first and second waveguide apparatuses, first and second projection subassemblies configured for introducing first and second light beams respectively into the first and second waveguide apparatuses, such that at least a first light ray and at least a second light ray respectively exit the first and second waveguide apparatuses to display first and second monocular images as a binocular image to the end user, and a light sensing assembly configured for detecting at least one parameter indicative of a mismatch between the displayed first and second monocular images as the binocular image.