Manufacturing of lenses
The main component of mineral glass is sand (silica or silica oxide), mixed with other substances in order to modify their properties. Thus, oxides of lead, titanium or lanthanum can be added to increase the refractive index, achieving thinner glasses; Fluorides or barium oxides to improve chromatic dispersion, improving optical quality; iron, cobalt, vanadium or manganese to give color; bromine, chlorine or fluorine halides to make photochromatic glasses (change color depending on the amount of light to avoid glare).
Once the mixture is made, it is deposited in an oven at a temperature between 1400 to 1500 ºC and then cooled quickly by reaching the material of the glass.
Organic lenses, these are made from different monomers. Plastic material in a liquid state is placed in molds and heated in an oven for a period of time so that it solidifies in a lens.
The exception is the polycarbonate, which is a solid thermoplastic material. Then, it must first warm up so that a liquid is returned and then it is quickly injected into the molds.