What a great kumihimo braiding project! Create your own beautiful braid to hold your eyeglasses, then attach end caps to each end of your braided cord; finally attach these to the end caps with jump rings. They will stretch to slip gently onto your frames.
Package of 6 holders (enough for 3 pairs of glasses).
These are a nice design of both the strap and the decorative ball. Here's a close-up picture so you can see the detail:
