1. An eye-imaging system, comprising: a camera system positioned in a head-worn computer and positioned to capture eye-image light that originates as reflections from an internal portion of an eye of a user, wherein the camera system comprises an antireflection coated optic to reduce reflections from a surface of the eye of the user to increase the sensitivity of the camera system to the reflections from the internal portion of the eye of the user, wherein the head-worn computer comprises a see-through computer display through which the user is able to see a surrounding environment and upon which the user is able to see digitally presented content; an infrared (IR) light-source positioned in the head-worn computer for projecting IR light into a common optical axis with the digitally presented content in-line with the eye of the user such that it irradiates the internal portion of the eye of the user with a known amount of IR light to produce the reflections from the internal portion of the eye of the user; and a processor adapted to analyze a light absorption statistic based on a comparison of the known amount of IR light and the reflections from the internal portion of the eye of the user.