Welcome to the Glass Age

44 transfer such as fast broadband internet, also work by bending light. Those same fibres are used in keyhole surgery and endoscopic diagnoses. The thin glass fibres enable surgeons to see clearly around corners to carry out procedures through very small incisions. This not only reduces scarring but also the chance of infection. The flexibility of the fibres means clinicians can insert the arthroscope in a safe entry point, such as the thigh, and navigate their way to the critical organ where to perform surgery, including life-saving heart surgery. Another serious risk to life is severe allergies that can cause anaphylaxis and fatal collapse of upper respiratory tracts. Approximately 20% of the European population suffer from chronic allergies, and another million people are estimated to have allergies unbeknown to them which can develop at any time. Commonly known by a brand name “EpiPen ® ” (Figure 3.1), syringes can rapidly administer a dose of life-saving adrenaline (epinephrine). The action of injection is a jab into the upper thigh, usually through layers of clothes, as rapid administration is critical in severe cases. This requires not only a high- strength needle but also a shatterproof cartridge that contains the drug (Figure 3.1). The cartridges are made of borosilicate glass for its chemical stability, so it does not alter the chemistry of the drug, but conventional borosilicate glass would shatter in about 10% of applications. The use of high-strength chemically toughened glass, made using a process similar to chemically tempered cover glass production for mobile phone screens, means that fracture is almost impossible when the EpiPen ® is used. At the time of writing, the world is suffering a global pandemic where efficacy, safety and distribution of vaccines have been in the spotlight. Figure 3.1. An EpiPen ® with its chemically toughened glass cartridges (white box); inset: a vaccine vial. Source: EpiPen ® courtesy of Saxon Glass Technologies (US); inset courtesy of GIMAV/VITRUM (Italy).