Eyeglass lenses are glass or plastic optical items that fit inside eyewear frames to enhance and/or correct the wearer’s vision. The magnifying glass, invented in the early 1200s, was the first optical lens used for enhancing vision. Made from a transparent quartz and beryl lens, the invention revealed the critical discovery that reflective surfaces ground to certain angles could enhance vision. Following this invention, Alessando di Spina introduced eyewear to the general populace.
Due to the increasing demand for eyewear, quartz and beryl lenses were virtually replaced by glass lenses. The convex lens was the first optical lens used in glasses to aid the correction of farsightedness, but other corrective lenses followed, including the concave lens for the correction of near-sightedness, and more complex lenses for the correction of astigmatism as well as the invention of bifocals by Benjamin Franklin in 1784.
More than 80 percent of all eyeglasses worn today have plastic lenses, but plastic lenses have not always been the lens of choice. The glass lens remained dominant until 1952, when plastic lenses were introduced. The plastic lens rapidly grew in popularity because the lens was lighter and less prone to breakage. Today, the manufacture of plastic eyeglass lenses far exceeds the manufacture of glass lenses, but the process has remained much the same for both types. Plastic as well as glass lenses are produced by successive stages of fine grinding, polishing, and shaping. While the same process is used to produce lenses for telescopes, microscopes, binoculars, cameras, and various projectors, such lenses are usually larger and thicker and require greater precision and power.
The manufactured or synthetic plastics are often designed to mimic the properties of natural materials. Plastics, also called polymers, are produced by the conversion of natural products or by the synthesis from primary chemicals generally coming from oil, natural gas, or coal. Sunglasses also fall into this category.
Without the use of plastics in the production of eyeglasses, where would we be? Perhaps permanently blind like some anti fossil fuel (Petroleum) activists are today!
Without natural gas and crude oil (fossil fuels) the range and proliferation of eyeglasses to virtually everyone on the planet would not be possible, leaving many to wonder why activists demonstrate against fossil fuels!
Where would we be without the Oil and Gas Industry?