The glass cover definitely helps with eyestrain. Unfortunately, on the iPhone 13 mini model, it also covers the speaker on the top of the screen, so it does muffle calls. I thought it was just an issue with mine, as the picture shows the cutout leaving room for the ear speaker, so I wrote to them for a replacement. They were super friendly and helpful in shipping out another, but it had the same issue, so I think that's just a design flaw. The screen is really nicely made and is very easy to apply, and if not for the speaker issue, it would be perfect! If you don't make many phone calls or if you use headphones when you do, it wouldn't be a problem.