For the perception of objects at different distances, the optical system of the eye must change its refractive power - in biology, a process called accommodation.
Interestingly, the viewing of stereoscopic video is also -accommodative reflex, and the eyes are trying to tune to an imaginary object. This leads to a conflict: both eyes try to focus on the screen because it is a place from where comes the light, and stereoscopic illusion. In the head-mounted display, for example, the effect can cause nausea and headaches in the case of considering an object, there is too close.
NVIDIA Corporation in conjunction with researchers from Stanford University intends soon to present a virtual reality helmet that will not cause accommodative- conflict. This helmet is based on stereoscope light field that Stanford scientists have already demonstrated previously.
Screens have two liquid crystal stereoscope matrix arranged in layers, so that the eye can perceive the depth of the scene. The decision gives researchers a more natural visual experience, but also reduces eye strain and reduces the likelihood of adverse effects.