Eyeglasses

The first recorded existence of eyeglasses is noted in the last decades of the 13th century in Italy. However, demand soared after the invention of printing in 1464 by Gutenberg where books became accessible to all, while in the 17th century the publication of the first newspapers led to a sharp rise in the trade of eyeglasses.

During the early period of eyeglasses frames were made of wood, horn and bone. Later, leather frames were released, as well as frames made of turtle shell, bronze, steel, silver and gold. Today most frames are made of hypoallergic plastic and metal alloys (nickel, copper, iron and manganese) as well as titanium, beryllium, aluminum and carbon fiber in many designs and colors. Some companies make a difference by making frames out of wood, horn and gold.

The manufacturing material of ophthalmic lenses of eyeglasses can be crystal or plastic. Crystal ophthalmic lenses offer excellent optical performance, but they are heavy and dangerous to break and injure the eyes. Nowadays, plastic ophthalmic lenses (polycarbonate and high refraction) are more popular because they excel in weight, thickness, safety and aesthetics without lacking lucidity and clarity.
The ophthalmic lenses of eyeglasses can have reflective coatings that help vision and increase the clarity of the lens as well as the perception of light contrasts.

Eyeglasses neutralize refractive vision problems such as myopia, hyperopia, astigmatism and presbyopia or a combination of these.
Eyeglasses can be monofocal, bifocal or multifocal (for one, two or all distances), white or photochromic (darken in the sun).