Originally Posted by Eric S.

"I thought the same thing until I spent some significant time fiddling with it, adjusting it and training myself in how to use it."

My issue is with eye focus. I need to wear my prescription glasses while riding, but my eyes can't focus on something a few inches from my face with them on.

Originally Posted by Leisesturm

The armchair physicist in me wonders if the eye is actually focused on the mirror, or instead, at the imaginary focus of the object in the mirror. I suspect the latter, from actual experience. Non-issue in other words.

Originally Posted by phughes

That is not an issue when looking at a mirror, unless you are trying to look at the edges of the mirror rather than the actual mirrored image. The distant mirrored image will be in focus because it is still a distant image. For example, if you need glasses for distance, you cannot simply remove your glasses, and look at a distant object reflected in a mirror, the reflected object will still be out of focus.