I also have perfect vision in terms of focal length - but it turns out I have astigmatism in opposite axises in both eyes. Glasses make a huge difference when

I also have perfect vision in terms of focal length - but it turns out I have astigmatism in opposite axises in both eyes. Glasses make a huge difference when watching TV, and are the dividing line between being able to tell the difference between 4K and 1080p and not being able to discern any.