A display subsystem for a virtual image generation system used by an end user, comprising: first and second waveguide apparatuses (110L, 110R, 170); first and second projection subassemblies (108L, 108R) configured for introducing first and second light beams respectively into the first and second waveguide apparatuses (110L, 110R, 170), such that at least a first light ray and at least a second light ray respectively exit the first and second waveguide apparatuses (110L, 110R, 170) to display first and second monocular images as a binocular image to the end user; a light sensing assembly (122, 122') configured for detecting at least one parameter indicative of a mismatch between the displayed first and second monocular images as the binocular image; and a frame structure configured for being worn by the end user, wherein the first and second waveguide apparatuses (110L, 110R, 170) are left and right eyepieces (110L, 110R) carried by the frame structure, wherein the frame structure comprises a frame that carries the left and right eyepieces (110L, 110R), and a bridge on which the light sensing assembly is affixed, wherein the frame structure comprises left and right cantilevered arms (310L, 310R) extending from the bridge, the left eyepiece being affixed to the left cantilevered arm, and the right eyepiece being affixed to the right cantilevered arm thereby rigidly decoupling the light sensing assembly (122, 122') from the first and second waveguide apparatuses (110L, 110R, 170), such that the light sensing assembly (122, 122') is agnostic to relative deformations between the first and second waveguide apparatuses (110L, 110R, 170). first and second waveguide apparatuses (110L, 110R, 170); first and second projection subassemblies (108L, 108R) configured for introducing first and second light beams respectively into the first and second waveguide apparatuses (110L, 110R, 170), such that at least a first light ray and at least a second light ray respectively exit the first and second waveguide apparatuses (110L, 110R, 170) to display first and second monocular images as a binocular image to the end user; a light sensing assembly (122, 122') configured for detecting at least one parameter indicative of a mismatch between the displayed first and second monocular images as the binocular image; and a frame structure configured for being worn by the end user, wherein the first and second waveguide apparatuses (110L, 110R, 170) are left and right eyepieces (110L, 110R) carried by the frame structure, wherein the frame structure comprises a frame that carries the left and right eyepieces (110L, 110R), and a bridge on which the light sensing assembly is affixed, wherein the frame structure comprises left and right cantilevered arms (310L, 310R) extending from the bridge, the left eyepiece being affixed to the left cantilevered arm, and the right eyepiece being affixed to the right cantilevered arm thereby rigidly decoupling the light sensing assembly (122, 122') from the first and second waveguide apparatuses (110L, 110R, 170), such that the light sensing assembly (122, 122') is agnostic to relative deformations between the first and second waveguide apparatuses (110L, 110R, 170).