spectacles

Spectacles, commonly called eyeglasses, are a vision-correcting device consisting of lenses mounted in a frame that rests on the ears and nose. They are worn to compensate for refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, and may also protect the eyes from glare, dust, or injury.

Lenses can be made from plastic or glass, with modern options including high-index plastics for thinner, lighter lenses. Common lens configurations are single-vision for a single distance, bifocal or trifocal for multiple distances, and progressive addition lenses (PALs) that provide a gradual change in power. Coatings such as anti-reflective, scratch-resistant, and UV-blocking layers are widely used, and some lenses incorporate photochromic transitions or blue-light filtering properties.

Frames are constructed from metal, plastic, or a combination, and come in full-rim, semi-rimless, or rimless designs. Frame materials and fit influence comfort, stability, and lens protection. The choice of lenses and frames depends on visual needs, lifestyle, and aesthetic preferences. The history of spectacles traces to 13th-century Europe, with Italian artisans credited with early designs; Benjamin Franklin popularized bifocals in the late 18th century, and later innovations led to progressive lenses and mass production in the 20th century.

Care and usage: spectacles require an optometric prescription and proper fitting to optimize vision and comfort. They should be cleaned regularly with a microfiber cloth and mild cleaning solutions, avoiding harsh chemicals. In certain activities, safety spectacles or sport-specific eyewear provide impact protection and extended coverage.