Bombentrichter
The parameters specified in a contact lenses prescription may include: * Material (eg. Oxygen Permeability/Transmissibility (Dk/L, Dk/t), water content, modulus) * Base curve radius (BC, BCR) * Diameter (D, OAD) * Power in dioptres - Spherical, Cylindrical and/or reading addition) * Cylinder axis * Centre Thickness (CT) * Brand