I put a significant effort to try and get an eyeglass mirror to work . Even used one for 2mo straight on my daily commute. But in the end that mirror was too much of a peripheral vision distraction for me that never went away - like that feeling someone has their hand next to your head and may slap you any second, or on a bicycle the feeling of a car approaching from the left when there wasn't one.
But also and equally problematic is I could never adjust it so I could glance at it and see behind me without contorting my head each time to see over shoulder. I was told it was not usable when in low position, so what is the point if I need to sit up right to see behind me?
With bar end mirror all it takes is a glance and no need to change positions. Still have a Take-a-Look in my storage bin in case I wish to try another time.