My understanding of it is that the eye-strain that people tend to get isn't from your eyes focusing on the glass, but rather due to the Vergence-Accommodation C

My understanding of it is that the eye-strain that people tend to get isn't from your eyes focusing on the glass, but rather due to the Vergence-Accommodation Conflict (VAC)[0]. Essentially, there's a mismatch between the vergence (a movement of both eyes in opposite directions simultaneously for a binocular-style effect), and the accommodation of the eye (the way your eyes change focus based on distance). When those two things aren't in alignment, you can get a feeling of eye-strain. The way the lenses bend the light make it so the focal length that you're focusing on is further than the screen in front of you, so that isn't what is causing the eye strain. Mind you, this is just my layman's understanding of the subject, so definitely take it with a grain of salt. [0] - https://en.wikipedia.org/wiki/Vergence-accommodation_conflict https://en.wikipedia.org/wiki/Vergence-accommodation_conflic...