An optical assembly is configured to receive visible scene light at the backside of the optical assembly and to direct the visible scene light on an optical path toward the eyeward side. The optical assembly includes a dimming element disposed on the optical path, where the dimming element includes a photochromic material that is configured to darken in response to exposure to a range of light wavelengths. A display layer is disposed on the optical path between the eyeward side of the optical assembly and the dimming element. The display layer is configured to direct visible display light toward the eyeward side and also to direct activation light to the dimming element, where the activation light is within the range of light wavelengths to activate a darkening of the photochromic material to dim the visible scene light.