Originally Posted by
BassNotBass
.... My vision is blurry at all depths other than a narrow range of 1.5' to 2' from my face. Beyond that I need distance lenses. Closer than that I need the progressive portions at the bottom of the lenses.
FWIW that is the definition of nearsighted, you can see clearly relatively closely (1.5-2') but need corrective lenses to see distance - no different than myself. The top half of our corrective glasses are to see distance clearly, and that's what we would use for a helmet mirror. The bottom/progressive part of our glasses are the magnified reading glasses portion which is typically required as most folks age.
..You say you are near-sighted... well of course you can see the helmet mirrors then, that's what near-sighted people can do.
This implies that you still believe you need to re-focus your eye on the mirror surface with is inches from your face, but that is not true, and the point I was trying to make. With the plane mirrors (flat or 1:1) typically used on eyeglass/helmet mirror, you use your normal distance/infinite focus to scan the road behind you, exactly same focus as looking forward up the road - you 'look through' the mirror focusing on a point whether it's 50 feet, yards, or miles away.
A very simple example is to use a regular bathroom or wardrobe mirror in your home. Focus on the reflection of an object behind you (through top half of your glasses) and you will be able to walk up to the mirror and touch your nose to the mirror with the object in prefect focus the whole time.