What is the refractive index of CR-39 lenses?

The refractive index of CR-39 lenses is indeed 1.499. This value is significant because the refractive index measures how much light bends as it passes through a material. A refractive index of 1.499 indicates that CR-39, a polycarbonate resin commonly used for making prescription eyewear, has a moderate ability to bend light compared to other lens materials.

This particular refractive index is crucial for calculations involving lens thickness, weight, and optical performance. Lenses with a lower refractive index generally result in thicker lenses for higher prescriptions, making CR-39 a popular choice for its balance of weight, comfort, and optical quality.

Understanding the correct refractive index is essential for eyecare professionals to ensure that prescriptions are filled accurately and that the final eyewear meets the visual needs of the patient.