FRAMES Frames can be made from metal or plastic, and they can be rimless. There is an almost unlimited variety of shapes, colors, and sizes. The type and degree of refractive correction in the lens determine to some extent the type of frame most suitable. Some lenses are too thick to fit in metal rims, and some large-correction prescriptions are best suited to frames with small-area lenses.

Rimless frames are the least noticeable type, and they are lightweight because the nosepiece and temples are attached directly to the lenses, eliminating the weight of the rims. They tend not to be as sturdy as frames with rims, so they are not a good choice for children, or for people who frequently remove their glasses and put them on again. They are also not very suitable for lenses that correct a high degree of farsightedness, because such lenses are thin at the edges.

Metal frames are less noticeable than plastic, and they are lightweight. They are available in solid gold, gold-filled, anodized aluminum, nickel, silver, stainless steel, and titanium and titanium alloy. Until the late 1980s, when titanium-nickel alloy and titanium frames were introduced, metal frames were, in general, more fragile than plastic frames. Titanium frames, however, are very strong and lightweight. An alloy of titanium and nickel, called Flexon, is strong, lightweight, and returns to its original shape after being twisted or dented. It is not perfect for everyone, though, because some young people are sensitive to its nickel content. Flexon frames are also relatively expensive.

Plastic frames are durable, can accommodate just about any lens prescription, and are available in a wide range of prices. They are also offered in a variety of plastics, including acrylic, epoxy, cellulose acetate, cellulose propionate, polyamide, and nylon, and in different colors, shapes, and levels of resistance to breakage. Epoxy frames are resilient and return to their original shape after being deformed, so they do not need to be adjusted as frequently as other types. Nylon frames are almost unbreakable. They revert to their original shape after extreme trauma and distortion; because of this property, though, they cannot be readjusted after they are manufactured.

FIT An individual should have the distance between the eyes (PD) measured, so that the optical centers of the lenses will be in front of the person's pupils. Bifocal heights also have to be measured with the chosen frame in place and adjusted on the person. Again, this is so that the lenses will be positioned correctly. If not positioned correctly, the individual may experience eyestrain, headache , or other problems.

Children may sometimes need a few days to adjust to a new prescription. However, problems should be reported, because the glasses may need to be rechecked.

Young people allergic to certain plastics should not wear contact lenses or eyeglass frames or lenses manufactured from that type of plastic. People allergic to nickel should not wear Flexon frames. Children and teens at risk of being in accidents that might shatter glass lenses should wear plastic lenses, preferably polycarbonate. (Lenses made from polycarbonate, the same type of plastic used for the space shuttle windshield, are about 50 times stronger than other lens materials.) Also, young people whose work places them at risk of receiving electric shock should avoid metal frames.

Retro-inspired frames have made a huge comeback this season. Think oversized square frames, cat-eye shapes, and bold aviators reminiscent of the '70s and '80s. These statement-making frames not only add a touch of nostalgia to your look but also exude confidence and sophistication. Pair them with your favorite outfits for an instant fashion-forward statement.