The 1.5 plastic material (often referred to as CR-39) used in photochromic lenses is a lightweight, cost-effective, and optically clear material that is ideal for mild to moderate prescriptions. It provides UV protection and can be further treated for scratch resistance and customized coatings, making it an excellent choice for photochromic lenses.

Refractive Index: The 1.5 refractive index is a standard for plastic lenses, making them lightweight and suitable for everyday use. While not as thin as high-index lenses (e.g., 1.61, 1.67), they still offer a comfortable and durable option for most prescription needs.

Lightweight and Comfortable: 1.5 plastic lenses are lightweight compared to glass lenses, reducing the overall weight of your eyewear for all-day comfort.

Optical Clarity: They provide clear vision with minimal distortion, offering satisfactory optical performance for a wide range of prescriptions.

Light-Adaptive Lenses: Photochromic lenses are designed to darken when exposed to UV light (e.g., sunlight) and lighten indoors or in low-light conditions. This allows you to wear the same pair of glasses in both bright and indoor settings without needing to change to sunglasses.