An electronic device may include a liquid crystal display, a photosensor, a light, and a controller. The liquid crystal display may have first and second transparent substrates and a liquid crystal material between the first and second transparent substrates. The photosensor may be on a portion of the first transparent substrate so that the first transparent substrate is between the photosensor and the second transparent substrate, and the light may be configured to provide illumination for the electronic device. The controller may be coupled to the photosensor and the light, and the controller may be configured to vary an intensity of the illumination from the light responsive to an intensity of light incident of the photosensor. Related displays are also discussed.