Plexiglass is a common name abbreviated as PMMA. the chemical name of this polymer transparent material is polymethyl methacrylate, a polymer compound formed by the polymerization of methyl methacrylate. It is an important thermoplastic that was developed earlier. Plexiglass also has a wonderful medical use in the manufacture of artificial corneas. If the clear cornea of the human eye grows full of opaque material, light cannot enter the eye. This is the blindness caused by total corneal leukoplakia, and the disease cannot be treated with drugs. As a result, medical doctors envisioned replacing the cornea with an artificial cornea that is full of white spots. The so-called artificial cornea, is a transparent substance made of a few millimeters in diameter only a mirror column, and then in the cornea of the human eye to drill a small hole, the mirror column fixed in the cornea, the light through the mirror column into the eye, the human eye will be able to regain the light. As early as 1771, there are ophthalmologists with optical glass made of lens column, implanted in the cornea, but did not succeed. Later, the use of crystal instead of optical glass, but also only six months after the failure. In World War II, when some airplanes crashed, the cockpit covers made of Plexiglas on the planes were blown up, and pieces of Plexiglas were embedded in the eyes of the pilots. After many years, although these fragments have not been removed, but also did not cause further inflammation or other adverse reactions in the human eye. This fortuitous event demonstrated the good compatibility between Plexiglas and human tissue. At the same time also inspired ophthalmologists, can use plexiglass to manufacture artificial cornea, it's good light transmission, chemical stability, non-toxic to the human body, easy to process into the desired shape, and can be compatible with the human eye for a long time. Artificial corneas made of plexiglass have been commonly used in clinical practice.