CR-39 (chemical formula: polycarbonate ethylene) is a type of plastic lens material used in eyeglasses and sunglasses.
It is lightweight, impact-resistant, and has a high Abbe value, which means it has low levels of chromatic aberration (color distortion) and provides good visual clarity.
CR-39 lenses are also relatively affordable compared to other lens materials, making them a popular choice for prescription and non-prescription eyewear.
They are suitable for both single vision and progressive lenses, and can be treated with various coatings such as scratch-resistant and anti-reflective to enhance their durability and performance.