While half-rimless glasses are a bold, fashionable choice, they can also be difficult to own because they're less durable than normal frames. Some are drill mounted and sturdy, but most half-rimless frames are held together by a small nylon cord, usually on the bottom half of the lens. This cord can easily slip out of place, causing the lens to slip out. Fixing this problem takes some concentration, but once you know how, it's not a difficult task. Step 1 Grasp the intact lens between your thumb and forefinger, placing your thumb around the bottom edge and your forefinger around the top. Keep a firm grip. Step 2 Gently grasp the lens that has fallen out and fit it against the top half of the frame. Step 3 Very carefully, work the nylon cord around the bottom edge of the loose lens, fitting it securely into the groove on the underside of the lens. This may take a few tries, but be patient. Step 4 Once the rim is firmly in place, use a lens-cleaning cloth to wipe off any smudges.