This paper proposes that the way of imaging on retina in virtual environment(VE) is the combination of both the imaging way of the real world and that of planar images. Since the binocular parallax is important for the three-dimension depth perception

we found that the problem with conventional VE in vision lies in the inconsistency of divergent degree of light with the binocular status. It is also emphasized that the reason of that conventional VE easily causes some persons dizziness and eyestrain is because virtual objects usually make binocular vergence and accommodation conflict. At last

this paper lists and analyzes some factors which might bring discomfort such as delayed effects

resolution

interpupillary distance and so on.