Eye imaging in head worn computing

An eye-imaging system for a head-worn display, comprising:

• a light source adapted to produce image light;
• and
• a partially reflective and partially transmissive surface adapted to direct the image light to an eye of a user of the head-worn display to present an image to the user,
• wherein directing the image light to the eye of the user comprises causing the image light to
• enter the partially reflective and partially transmissive surface via a first side of the partially reflective and partially transmissive surface,
• leave the partially reflective and partially transmissive surface via a second side of the partially reflective and partially transmissive surface, the second side different from the first side, toward the eye of the user, and
• reflect in the eye of the user to form an eye-image light, and
• wherein the partially reflective and partially transmissive surface is adapted to receive on its second side a reflected eye-image light reflected from the eye of the user and to reflect the reflected eye-image light towards a camera, and wherein the camera is positioned to capture the reflected eye-image light to capture an image of the eye of the user.