Glasses

Glasses, or spectacles, are a portable optical device worn on the face to correct refractive errors or provide ocular protection. They consist of lenses set into a frame that rests on the nose and ears, with temples that extend behind the ears. Lenses are typically made of glass or plastic and are ground to a specific prescription. Common configurations include single-vision, bifocal, trifocal, and progressive lenses.

History and development: The earliest credible evidence of spectacles dates to the late 13th century in Italy, with lensmakers in cities such as Venice. Ground glass lenses were mounted in frames to aid reading and distance viewing, enabling longer-term wear. Over time, designs evolved toward lighter materials, smaller frames, and better fit, reflecting advances in optics and eye care.

Types and uses: Eyeglasses are primarily used for vision correction but also include sunglasses that block UV rays, safety glasses for industrial use, reading glasses, and sport or children’s frames. Some lenses include coatings such as anti-reflective or scratch resistance, and others are photochromic, blue-light filtering, or polarized to reduce glare.

Prescriptions and fit: An eye care professional determines the required prescription through a refraction test and measures pupillary distance. Proper fit considers frame size, nose bridge, and temple length to ensure comfort and correct lens alignment. Regular checks are advised as prescriptions or facial measurements can change over time.

Maintenance and care: Lenses should be cleaned with a microfiber cloth and mild soap and water or compatible cleaners. Avoid harsh solvents that can damage coatings. Store glasses in a protective case when not in use and have frames adjusted by an optician as needed. Safety glasses may meet specific impact standards for certain activities.