One drawback to wearing eyeglasses is that with constant wear, the tiny screws that hold the frame together tend to loosen. There's an easy way to fix this.
Buy an eyeglass repair kit. You can find kits at the pharmacy or in the jewelry section for a few dollars. This contains a tiny screwdriver designed to fit eyeglass screws, several screws in varying sizes, a small magnifier and other replacement parts. This kit generally comes in a small plastic pouch that fits neatly in a purse or pocket.
Make emergency repairs when you don't have a repair kit by using the tip of a thin-blade knife, a paper clip (although this is a bit more difficult) or a thin fingernail file. Use care not to strip the head of the screw. Tighten until the screw is secure, but avoid over-tightening as you may strip the screw.
Replace screws that loosen repeatedly. Cover your work area with a sheet of paper to make finding dropped screws easier. Remove the old screw, select a new screw in the same size and insert the new screw. Grip the frames and gently squeeze them to hold the frame in place. Tighten the screw until the frame is secure.
Examine your glasses weekly for loose screws. Use the screwdriver to tighten the screws.