What material is commonly used for rigid gas-permeable contact lenses?

The commonly used material for rigid gas-permeable contact lenses is polymethyl methacrylate (PMMA). This synthetic polymer was one of the first materials used for rigid contact lenses due to its excellent optical clarity and durability. However, modern advancements have shifted towards using materials that allow for increased oxygen permeability, leading to the development of gas-permeable lenses that still utilize sophisticated variations of PMMA but incorporate other elements for enhanced breathability.

While PMMA itself does not allow for oxygen transmission, it serves as a foundational material in the creation of gas-permeable lenses. Gas-permeable lenses are specifically designed to allow more oxygen to reach the cornea, which is vital for eye health. The options like silicone hydrogel and hydrogel are primarily associated with soft contact lenses, and polycarbonate is used in various applications but is not a common choice for rigid gas-permeable lenses. Thus, while PMMA is traditionally recognized as a significant material in lens development, it's essential to relate it back to its role in gas-permeable designs.