Target doesn't sell these, but I have found the best line of sight, most versatile (for eyeglasses) mounting and easiest adjustment from a mirror called "Take a Look." None of the Frankenstores sell it, you will have to bite the bullet and go to a real bike store.
Bonus; if you live in or are fortunate enough to travel to a country where you must ride on the left side of the road, this mirror can be completely inverted to work on the right temple of your glasses.