We will be starting a series of articles to provide information on vision care. May they be useful to some! The first article we are featuring concerns frame materials.
Types of Frame MaterialsWhen choosing a pair of spectacle frame or sunglasses, are you influenced by the type of material the frame is made of and are you aware of the benefits and shortcomings associated with these materials?
Metal and plastic are the two predominantly types of materials used in the manufacturing of frames. In general, metal frames are lighter in weight and they keep their adjustments better than plastic frames. Plastics frames, on the other hand, being thicker and more rigid can offer a more dramatic and stylish look. The wide range of colours being offered, together with interesting designs and intricate details frequently seen on the broad temples of designer eyewear, make plastic frames ever popular. Most designer eyewear are available in these two materials or the combination of both. There is a third type of frame material that is more exotic and is derived from nature. More details can be found in the rest of the article.
Metal FramesMetal frames can be made of different types of metals, but the most common ones are made out of nickel silver, although increasingly materials such as titanium and stainless steel are being used. For tropical countries like Singapore, nickel silver may not be the ideal material of choice as high humidity causes the frame to tarnish easily. Also, nickel silver frames are susceptible to corrosion when they are exposed to perspiration. Skin that comes into contact with the corroded portion can experience skin sensitivity (common symptoms will include redness of the skin) and in a more serious case, an allergic skin rash may develop. Approximation 10% of the general population experiences nickel-related allergies.

Another metal frame material that is worthy of a mention is titanium. Currently, titanium represents about 25% of the eyewear market in the United States. This metal, apart from being light and biocompatible, possesses excellent strength, corrosion resistant and flexibility. Titanium frames are also hypoallergenic. Pure titanium frames (>90% Ti by weight) are very expensive. As such, it is common to find titanium alloy frames in the market. Beta titanium is an alloy of titanium, aluminum (added to make the frame light), and vanadium (for hardness). The primary benefit of beta titanium is the enhanced mechanical flexibility that allows the fabrication of very thin frame. Memory metal frames are alloys of nickel and titanium. These frames have extraordinary elasticity and can retain their shape superbly well. As they are less likely to break, they are excellent choice for children and active people.
Plastic Frames
Most plastic frames, sometimes known as shell frame, are machine manufactured while the more exquisite ones are being hand-made. Almost all plastic materials used can be softened with heat for the purpose of lens insertions and adjustments. Most plastic frames do not come with nosepads which fit individuals with high nose bridge very well. However, for Asians who tend to have flatter nose bridge and flared noses, these frames may not fit comfortably as inadequate support can result in the frame slipping down the nose.
Plastic frames are mainly made of cellulose acetate which can come in many colors and shapes. Frames made of this material are durable and they can be designed to offer high transparency as well as deep gloss. They also feel more natural than some other types of synthetic materials and thus retained their popularity as a material of choice.

There are more exotic plastic frame materials that include nylon and propionate but we are going to just mention about two others here- polyamide and epoxy.
Polyamides are synthetic plastics approved for use by the FDA. The material has the necessary properties to be made into frames that are extremely light-weight and flexible while at the same time retain their shape very well. Frames made from these materials possess very good breakage-, scratch- and chemical-resistance, hence, making them a good choice with individuals who have sensitive or/and allergic skin conditions. Such material forms the core technology in Swissflex’s range of eyewear.
Epoxy frames (more commonly known as “memory plastics”), like their memory metal frames counterpart, are strong and has the ability to return to their original shape after being deformed. As such, they offer the advantage that the frame does not require to be re-adjusted as frequently as some other types.
Natural Materials
Materials derived from buffalo horns and turtle shells are occasionally still being used, even though this has become less common as conservation of these animals gained momentum. The demand for these frame materials arises on the principle of exclusivity- no two pieces are identical. They offer the individual the opportunity of owning a “signature” piece and as each piece is hand-crafted they command a very high price. Since these materials are derived from nature, they are extraordinarily kind to the skin. Buffalo horn and turtle shell frames are also light-weight and they offer great wearing comfort. Some even believe that they offer some medicinal benefits!
