The frame materials for glasses fall into 2 main categories; metals and plastics.
Pure titanium frames are ultra light, nickel free, hypo-non-allergenic and have excellent tensile strength. The material is used to create the perfect equilibrium between strength and comfort.
Titanium alloy frames, including memory metal frames, are ultra light, have superb memory shape retention and are extremely durable. These frames give a peerless tensile strength and will perform and excel in extreme circumstances.
Stainless steel - lightweight, strong, durable - is often used to create ultra thin frames due to its excellent tensile strength and durability.
Monel ( blended alloy) is used to manufacture most of the frames available in the world today. In its best form this malleable material is strong and durable, and, though it does contain some nickel (many cheaper frames contain significant levels of nickel which can cause skin irritation), the plating found in the better quality frames give a superb barrier between the wearer and the base metal.
SPX, a plastic made famous by the prestigious frame manufacturer Silhouette, is the lightest plastic used for spectacle frames. SPX is extremely strong, hypo-non-allergenic and - due to its high resistance to perspiration absorption - retains its colour and lustre particularly well.
Optyl is an extremely light and durable, high quality plastic. Optyl is available in a vast array of both solid and translucent colours. Optyl resists perspiration as well as retaining its shape extremely well.
Cellulose Acetate and Proprinate are the most widely used plastics to create spectacle frames. These materials are available in an almost infinite range of colours, from the layered colour combinations (laminates) to the solid colours. The material is also perfect for cutting and shaping to create intricate shapes and creative styling.
The most common material for frames are plastic, metal and a combination of both. Generally, plastic frames are lighter and less expensive, and also require less maintenance than metal ones. People who are allergic to certain metals are inclined to choose plastic ones. If you want to keep eyeglass frames for a long time, you can take metal frames into account because certain types of plastic ones may contract or expand under temperature changes.