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Glasses, also known as eyeglasses and spectacles, are vision eyewear with clear or tinted lenses mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms, known as temples or temple pieces, that rest over the ears. Man with glasses. Glasses are typically used for vision ...
The history of glass-making dates back to at least 3,600 years ago in Mesopotamia. However, most writers claim that they may have been producing copies of glass objects from Egypt. [1] Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. [2]
History of optics. Modern ophthalmic lens making machine. Optics began with the development of lenses by the ancient Egyptians and Mesopotamians, followed by theories on light and vision developed by ancient Greek philosophers, and the development of geometrical optics in the Greco-Roman world. The word optics is derived from the Greek term ...
In the 1790s, the O'Hara and Craig glass works was the first glass works in Pittsburgh, and this works was another early user of coal as a fuel for its furnaces. [67] By 1800, it is thought that roughly ten glass works were operating in the United States. [68] Challenges for American glass works revolved around labor, raw materials, and imports.
Glass is an amorphous (non-crystalline) solid. Because it is often transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass like "a glass" of water, "glasses", and "magnifying glass", are named after the material. Glass is ...
Bifocals. A bifocal lens with areas of differing magnification. Bifocals with separate lenses. In this case, the Swedish ethnologist Jan-Öjvind Swahn [sv]. Bifocals are eyeglasses with two distinct optical powers. Bifocals are commonly prescribed to people with presbyopia who also require a correction for myopia, hyperopia, and/or astigmatism.
Hunter S. Thompson was known for wearing yellow-tinted driving glasses. When driving a vehicle, particularly at high speed, dazzling glare caused by a low Sun, or by lights reflecting off snow, puddles, other vehicles, or even the front of the vehicle, can be lethal. Sunglasses can protect against glare when driving.
Aviator sunglasses. F.W. Hunter, Army test pilot, with AN 6531 sunglasses (1942) Aviator sunglasses are a style of sunglasses that was developed by a group of American firms. The original Bausch & Lomb design is now commercially marketed as Ray-Ban Aviators, although other manufacturers also produce aviator-style sunglasses.