Captions are projected at a perceived distance and that can vary according to each user, so it's hard to set a definitive minimum vision score.
XanderGlasses project captions outward, at a perceived distance which can vary according to individual user, so we don’t have a hard and fast guide for minimum Visual Acuity Score. People with various vision abilities use the glasses successfully. And we offer prescription lenses for several common conditions. People with severe astigmatism may find the glasses disorienting.