what are glasses lenses made of

Glasses lenses can be made of different materials, including plastic, glass, and high-index polymers. Plastic lenses are the most common and come in four types: polyethylene, Trivex, polycarbonate, and high-index polymers. Polycarbonate is a type of plastic that is transparent, easily molded, and impact-resistant, making it a popular choice for optical lenses, especially for children or adults prone to accidents. Glass lenses, made from natural mineral glass, are less common but still have their place in optometry today thanks to their exceptional scratch resistance and lower cost compared to plastics. Glass lenses also provide the clearest vision with the smallest amount of distortion, but they are heavier and more fragile than plastic lenses. High-index plastics are another type of lens material that offers a higher refractive index, meaning a thinner lens, but they are also heavier due to the higher density of these plastics. The choice of lens material depends on various factors, including the patients age, occupation, prescription, and frame design.