Ah. Definition of ‘healthy’ people please.
Obviously for screens to have an effect one must have a migraine/MAV predisposition and I agree The Perfect Human Specimen wouldn’t have a problem. Unfortunately we’re not all perfect beings. It only needs an existing predisposition combined with some other slight affect on the vestibular system to render the latter unstable. Many people have very minor physiological flaws which can compromise their vestibular systems which can, combined with a predisposition, in certain circumstances like excessive computer screen time, bring on various medical conditions. Many years ago my chronic sciatica was attributed to sitting 40-50 hours a week at a computer terminal barely moving for 5-6 hours at a stretch. Physio told me human body is not designed for such inactivity. Change of occupation which reduced sitting to about 60% worked wonders. So I remain convinced excessive screen time can push what is already a compromised vestibular system over the edge and once activated more of the same will keep the cycle running. Same principle.