It hurts to look at the sun.

I don't see necessity to require this is solar-powered, but I do think a contact lens mounted display sounds good. But it would be nearly impossible to do with current technology.

I don't know how you'd ever focus your eye at a zero-distance (is this possible?) but I do know that getting even a 640 x 480 pixel-count into an area the size of about half-your pupil (which changes size BTW) would be amazing.

this is and excerpt from eyetap.org. Its the only device that currently matches your description.

"EyeTap is a device which allows, in a sense, the eye itself to function as both a display and a camera. EyeTap is at once the eye piece that displays computer information to the user and a device which allows the computer to process and possibly alter what the user sees. That which the user looks at is processed by the EyeTap. This allows the EyeTap to, under computer control, augment, diminish, or otherwise alter a user's visual perception of their environment, which creates a Computer Mediated Reality. Furthermore, ideally, EyeTap displays computer-generated information at the appropriate focal distance, and tonal range. The figure below depicts and describes the basic functional principle of EyeTap. Note from the diagram that the rays of light from the environment are collinear with the rays of light entering the eye (denoted by the dotted lines) which are generated by a device known as the aremac. "aremac" is the word camera spelled backwards and is the device which generates a synthetic ray of light which is collinear with an incoming ray of light. Ideally, the aremac will generate rays of light to form an image which appears to be spatially aligned, and appears at with the same focus as the real world scene."