3 terms
IPD, or interpupillary distance, is the distance between the centers of the pupils, which an XR headset must match for a sharp and comfortable image.
Vergence-accommodation conflict is the mismatch in XR headsets between where the eyes converge and where they focus, causing eye strain and blurred near views.
VR motion sickness is the nausea and discomfort some users feel in virtual reality when what the eyes see conflicts with what the inner ear senses.