Cheap eyeglasses near me, also known as spectacles or spectacles, are lenses in frames that are worn in front of the eyes to aid vision or correct vision defects such as nearsightedness, farsightedness, and astigmatism. Roger Bacon made the earliest recorded comment on the use of lenses for optical purposes in 1268, but by this time both Europe and China were using magnifying buy cheap eyeglasses near me inserted into frames for reading, and whether the West borrowed this practice exists dispute. East or vice versa. In Europe, cheap eyeglasses near me first appeared in Italy, whose invention is attributed to Alessandro di Spina in Florence. The first portrait to show spectacles is Tommaso da Modena's 1352 portrait of Hugh of Provence. In 1480 Domenico Ghirlandaio painted St. Jerome on a table with spectacles hanging on it; as a result, St. Jerome became the patron saint of the guild of spectacle makers Patronus. The earliest cheap eyeglasses near me had convex lenses to help with distance vision. The concave lens used for short-sightedness, or short-sightedness, first appears in Raphael's 1517 portrait of Pope Leo X.

In 1784, Benjamin Franklin invented bifocal cheap eyeglasses near me, which divided the lenses into long-sighted and short-sighted lenses, and the separate parts were held together by the frame. Cemented bifocals were invented in 1884, fusion and integral bifocals followed in 1908 and 1910, respectively. New designs of trifocals and bifocals were later introduced, including the revival of the Franklin bifocal in a one-piece form.
Initially, lenses were made from clear quartz and beryl, but increased demand led to the adoption of optical cheap eyeglasses near me, with Venice and Nuremberg being the main production centers for optical cheap eyeglasses near me. In 1885, Ernst Abbe and Otto Schott demonstrated that the addition of new elements to a cheap eyeglasses near me melt resulted in many desirable changes in the refractive index and dispersive power. In the modern process, lens glass is first rolled into sheet form. Most lenses are made of clear crown cheap eyeglasses near me with a refractive index of 1.523. In high myopia correction, cosmetic improvements can be achieved if the lenses are made of dense flint cheap eyeglasses near me (refractive index 1.69) and coated with a thin film of magnesium fluoride to eliminate surface reflections. Flint cheap eyeglasses near me or barium crowns have lower dispersion power and are used in fused bifocal lenses. Plastic lenses are becoming more popular, especially when lens weight is an issue, and plastic lenses are more shatterproof than glass lenses. In sunglasses, the lenses are tinted to reduce light transmission and avoid glare. See also contact lens; lens.