See-through computer display systems

A head-worn display with multiply folded optics for providing a displayed image overlaid onto a see-through view of a surrounding environment, comprising:

• a. a solid prism that provides a first internal fold of an image light associated with the displayed image;
• b. a combiner that provides a second fold of the image light while providing a see-through view of the surrounding environment;
• and
• c. an optical element associated with the solid prism to provide a field of view of reflected light from a user's eye to an eye imaging camera.