History & Technology of LifeRx Lenses

In 2005, Vision-Ease Lens Introduced LifeRx photochromic polycarbonate lenses. The photochromic dye used in LifeRx lenses has been specially formulated using a single organic molecule rather than a mix of several different colored molecules as is often the case. Utilizing a single dye provides a clear-as-liquid color when inactivated, as well as color consistency throughout activation, and fast fadeback. As a result, LifeRx lenses are as clear as a clear polycarbonate lens when fully deactivated and they don’t become an unusual color during activation, fadeback, or as they age. In the manufacturing of LifeRx photochromic lenses, this special dye is combined with a polymer to form a flexible film that allows the dye to easily change its configuration when exposed to UV light. This film is then molded between strong layers of polycarbonate and fused onto an ophthalmic lens during the lens molding process.

Encapsulation Technology

This patented photochromic technology was developed by Vision-Ease Lens specifically for the use in the manufacturing of photochromic polycarbonate lenses. This technology consists of introducing a photochromic film to a polycarbonate lens during the molding process. As a result the photochromic layer is 0.4 mm below, rather than on, the front surface of LifeRx lenses. This ensures that the photochromic dye is protected behind a strong layer of polycarbonate.

How Photochromic Dyes Work

Photochromic dyes work by changing their chemical structure when exposed to UV light. When these special molecules are exposed to UV rays, they undergo a chemical process that causes them to change shape. The new molecular structure absorbs portions of the visible light, causing the lenses to darken. The number of molecules that change shape varies with the intensity of the UV rays. In the absence of UV light, the molecules change back to their original form. Photochromic dyes will change back to their original form faster at higher temperatures.