Optical glass can change the propagation direction of light and can change the relative spectral distribution of ultraviolet, visible or infrared light. Optical glass in a narrow sense refers to colorless optical glass; optical glass in a broad sense also includes colored optical glass, laser glass, quartz optical glass, anti-radiation glass, ultraviolet and infrared optical glass, fiber optical glass, acousto-optic glass, magneto-optical glass and photochromic grass. Optical glass can be used to manufacture lenses, prisms, mirrors and windows in optical instruments. Components made of optical glass are key elements in optical instruments.