Lenses - Lens Materials - Lens Types - Treatments and Coatings

Lens Materials

Lenses can be made of plastic (CR39), glass, polycarbonate or new ‘Phoenix’ materials, and are available in a variety of indices that determine the lens thickness.

Plastic lenses are the standard lens used in spectacles. They are light, strong and cheaper than other materials, however they are the most easily scratched. Glass lenses are scratch resistant but are rarely used as they are much heavier than plastic and have a risk of shattering. Increasingly lenses are made from polycarbonate or Phoenix materials that are lighter, stronger and more scratch resistant than standard plastic lenses. They also have in-built UV protection and are thinner than regular plastic.

The index of a lens is a major factor in determining its thickness. Standard plastic lenses have an index of 1.5. The higher the index the thinner the lens will be, with an index of 1.6 being significantly thinner than 1.5, and 1.7 being very thin. People with strong prescriptions need to use higher index lenses to achieve a cosmetically pleasing result. High index lenses also have in-built UV protection.