Spectacles or specs are fundamentally a set of frames containing a couple of lenses borne in front of the eyes, commonly for vision correction, eye protection, or alternatively for protection from harmful UV rays.

In the old days, people used a variety of systems to get the corrective lenses to stay in front of their eyes. Nowadays, people have settled on largely the same system for their Spectacles, which consist of the frame sitting on the nose, with hooks around the ears to help both eyes see well.

Eyeglass frames are usually constructed from metal or plastic. Optical lenses were initially produced using glass, but many are now made from varying types of metal plastic, including CR-39 and polycarbonate. These materials reduce the danger of breakage and weigh less than glass lenses. Some plastics also have more advantageous optical properties than glass, such as better transmission of visible light and greater absorption of ultraviolet light.[1] Some plastics have a greater index of refraction than most types of glass; this is useful in the making of corrective lenses shaped to correct various vision abnormalities such as myopia, allowing thinner optical lenses for a given prescription. Modern plastic optical lenses, called izon, can also correct for the higher order aberrations that naturally occur within the surface of our eye. These lenses create sharper vision and help with the halos, starbursts, and comet-tails often associated with night time driving glare. Wavefront guided LASIK surgery also corrects for the higher order aberrations.

Scratch-resistant coatings could be applied to most plastic optical lenses giving them similar scratch resistance to glass. Hydrophobic coatings designed to ease cleaning are also gettable, as are anti-reflective finishes intended to reduce glare, improve night vision and make the wearer's eyes more visible.