Helmet mirrors? Tried them, don't like 'em. I spend too much time squinting at the little mirror and fiddling with it. I also tend to forget about what's in front of me. Same with eyeglass mirrors. Maybe I am so bad at using these mirrors because I wear glasses to correct a -12 diopter in both eyes (coke bottles). No, laser surgery (not possible) and contacts (don't want something floating on my eye) are not options (for me).
I haven't tried road bar mounted mirrors because I have observed them falling off or being so subject to vibration as to be useless. Also, my arms, when using the usual road bar hand positions, seem to block the mirror from any place I might reasonably mount it. Finally, the view from tube-mounted mirrors (under-the-leg views) will be blocked by my rear panniers.
Before brifters there was a mirror that bolted on the brake levers. This position would seem ideal, but I am agast at the idea of drilling holes into my STI Ultegras. Besides, this mirror has been discontinued (Mirrcycle).
After searching the web, I found the 3rd Eye which has a glass convex lens that mounts in the bar end. I assume that it could then be adjusted for road bars... Anyone have experience with the 3rd Eye?http://www.3rd-eye.com/(09).htm