Earpieces on eyeglasses are the ends of the temple piece/support arms that rest on top of and/or behind the ears. The term "earpiece" can also refer to the soft plastic sleeves that may encase the ends of each arm. Whatever your definition, earpieces help prevent your eyeglasses from falling off, or resting on your face at an angle. Replacing an earpiece depends entirely on what you mean by the term and the type of damage. The end of the arm can break or bend or the sleeve can fall off and become lost or crack with age.
Contact the store where you bought your eyeglasses and ask if the store can acquire a matching or similar replacement earpiece. Additionally, ask about the cost to purchase the part(s).
Order the parts over the phone and schedule shipping or pickup as the delivery method.
Wait to receive the parts in the mail or for a call to pick up the parts. Unpackage the parts after receipt.
Remove the old earpieces from your eyeglasses, if not already removed. Unscrew the entire support arm using your eyeglass kit, if replacing the entire arm, or grasp the end of the earpiece sleeve and simply slide it gently from the arm.
Attach the new piece. Screw on the new arm; or align the end of the arm with the hole at the end of the straight portion of the earpiece sleeve, insert the end into the hole and then carefully push the sleeve onto the arm without bending the end.
Repeat with the other arm or sleeve as needed and then put on your eyeglasses in front of a mirror. If the glasses feel too loose or don't look right on your face, grasp the earpiece gently between your thumb and index finger and bend it slowly inward -- retrying the glasses as you bend until the glasses rest without the earpieces rubbing your head or flaring too much. If the glasses feel too tight or rub the back of your head, bend the earpiece slowly outward. If the arm is the issue, bend it in/out or up/down slightly as needed until it rests comfortably against your head.