Techniques for operating an optical system are disclosed. World light may be linearly polarized along a first axis. When the optical system is operating in accordance with a first state, a polarization of the world light may be rotated by 90 degrees, the world light may be linearly polarized along a second axis perpendicular to the first axis, and zero net optical power may be applied to the world light. When the optical system is operating in accordance with a second state, virtual image light may be projected onto an eyepiece of the optical system, the world light and the virtual image light may be linearly polarized along the second axis, a polarization of the virtual image light may be rotated by 90 degrees, and non-zero net optical power may be applied to the virtual image light.