1. In an optical system comprising a light source, a light outlet, and an optical element disposed between the light source and the light outlet, a method of monitoring for optical system faults, the method comprising: detecting, via a light sensor directed toward an interface surface of the optical element closest to the light source, an intensity of light traveling from the interface surface of the optical element to the light sensor; comparing the intensity of light detected to one or more threshold intensity values; identifying an optical system fault condition based on comparing the intensity of light detected to one or more threshold values; and modifying operation of the optical system based upon the optical system fault condition, wherein modifying operation of the optical system includes one or more of changing a power state of the optical device and providing a warning message for display on a display device.