1: optical path. The image must not be focused or formed on the surface of the lens. The image should be formed on the retina with the eye relaxed, i.e. normally focused on infinity. This one may be getting closer, for people with 20/20 vision or better (seen the large HD projectors that can work from the floor right beside the wall?). But my relaxed focal distance is a little more complicated than that, and I certainly cannot focus down comfortably to 1 meter. In fact, I think anybody would have issues maintaining such a focus, and it would certainly interfere with seeing through the glasses to the real world at the same time.

2: Optical corrections. I have asymmetrical eye imperfections. One eye is long sighted, the other is short sighted. Both have 1 1/2 dioptres of astigmatism at about 60 degrees of axial tilt, but not the same orientation in both eyes. The projection system has to be able to work reflecting from the back of my prescription. Which implies conformable lenses in the projector. I think we have these for perfect optics, but not yet for corrective optics; also the corrective part has to be able to ‘uncorrect’ for the characteristics of the back of the eyeglass lens.

We will be there when I can use them without eye-strain. In my case, AFAIK, contacts are not an option, so I cannot simulate perfect eyeballs. Correcting for eyesight issues in instruments is a thorny issue. I am an amateur astronomer, and astigmatism is a real handicap. I tried once to make a filter using a previous prescription lens cut down to a circle to fit the 1 1/4″ filter holder, but it does not work when on the inside of the eyepiece; it needs to go between the eyepiece and my eyeball, and I did not find as satisfactory mounting solution for that configuration. Plus I am not functional when not looking through a telescope eyeiece without my glasses.

There are several head-mount displays trying to do the work, but they all suffer from these people problems. And AR also is going to need to overlay CGI into your actual field of view such that it lines up with real reality. I’m beginning to think Borg eyeballs may be the only way, and I certainly am not willing to give up an eyeball for the cause.