Lenses that darken in the sun? You may have heard of them, but you are probably skeptical about the real importance of having automatic sun protection without your intervention. In fact, especially for those who wear prescription glasses, protecting the eyes from the sun can become quite a hassle. Especially when in environments with different light intensities, having to choose between wearing sunglasses or clear lenses can cause difficulties.
Fortunately, for many years, solutions have been developed that allow for lenses that automatically darken in the sun, also known as photochromic lenses. Thanks to special adjustments, they become sensitive to light and change color based on the amount of UVA, UVB, and infrared rays received.
How do photochromic lenses work?
Thanks to a special treatment, photochromic lenses are coated with materials that through a chemical reaction darken or return to being transparent based on exposure to sunlight.
The reaction occurs upon contact with UVA, UVB, and infrared rays. Although it seems like a recent discovery, the first experiments were actually conducted in the 1960s!
As technology has advanced, the aesthetic performance, comfort, and speed of transition have improved.
In particular, the speed of transition from clear to tinted has been increased, achieving a complete transition from dark to clear (and vice versa) in just a few minutes.
Do photochromic lenses darken only in sunlight or also in artificially lit environments?
In the past, it was possible for glasses to darken even inside environments lit by artificial light, but today the lenses change color only when illuminated by the sun's UV rays.
Wearing photochromic lenses does not cause any discomfort inside your home or in the office; the glasses remain clear, and there is no noticeable difference compared to glasses with standard lenses.
Moreover, modern photochromic lenses like those created by Essilor combine darkening with protection from blue light, essential to avoid fatigue caused by excessive use of electronic devices.
Do they provide total protection from UVA and UVB rays?
Just like sunglasses, photochromic lenses offer total protection from UV rays.
However, there are specific situations where it is advisable to use sunglasses instead of photochromic ones: when engaging in outdoor sports and in situations of intense light, such as at the beach or in the mountains.
In fact, when doing outdoor sports and being in places where brightness and reflected light are very strong (for example, sailing at sea or road cycling), it is advisable to wear polarized glasses that provide complete coverage from UVA and UVB rays.