Spring hinges are hinges that are mounted around a tiny spring that helps to hold the frames on to the wearer's head more securely and are also able to sustain more wear-and-tear over time. They are an excellent choice for children's eyewear and those who are tougher on their glasses. Be aware, however, that because of the extra hardware involved, if spring hinges do manage to break, they are often more difficult to repair than standard hinges.
"Flex" frames-- also called "memory metals"-- are eyeglasses made out of a titanium alloy that allows the frame to be bent and twisted and still return to their original shape. They are an excellent choice for individuals who are rough with their glasses or often misplace them in ways that could lead to them being sat on or crushed.
Allergies and Frames
If you suffer from skin allergies, hypoallergenic metals such as titanium or stainless steel are good choices. In choosing a titanium frame, be aware that some "flex" titanium frames are actually composed of a nickel-titanium alloy that may not be hypoallergenic. Ask the opticians at Texas State Optical in Magnolia for details.