Photochromic lens - Transitions lens
Photochromic lenses
The photochromic lens is as clear indoors as ordinary lenses, and it is like sunglasses after changing color, which can provide protection for the eyes in the scorching sun. The degree of discoloration changes with the intensity of sunlight, giving the wearer a most suitable luminosity. Sunglasses can only reduce light across the board.
The principle of the photochromic lens is to electroplate a photochromic coating on the surface of the lens. This coating only reacts to ultraviolet light (UV) and changes color. The main outdoor light source is the sun. When the lens is exposed to ultraviolet rays in the sun, it will quickly start color transition. The depth of the color change is affected by the intensity of ultraviolet light. Without ultraviolet light, the lens will return to clear and transparent.
Although the photochromic lens is very convenient, its photochromic effect is mainly affected by the strength of ultraviolet rays. Take driving as an example. Generally, the windshield of a car can block most of the ultraviolet rays. Therefore, the photochromic lens may not change color in the cabin under the violent sun.
The color depth of the color changing lens depends on the intensity of the ultraviolet light. Hong Kong is humid, the ultraviolet rays reaching the surface are relatively weak, and the color depth of the photochromic lens is relatively light. In places with dry and noisy weather, the performance of photochromic lenses will be much better.
Transitions lenses (a wholly-owned subsidiary of Essilor) have become synonymous with photochromic lenses. For more than ten years, the coating discoloration technology on the market has only one full line of sight. The 8th generation has been released in 2020, and it is currently the best photochromic lens. It has the advantages of fast discoloration, deep color, uniform color and long lens life. The full-sight lens is a technology that is sold to the outside world, so in addition to Essilor, Hoya, Zeiss, Tokai and other brands will have Transitions' photochromic lenses. Even the Acuvue contact lenses have Transitions Ver.
Essilor - AS Transitions lens from $1399
Hoya launched its own technology of Sensity color lens series in 2014. 2020 will also usher in the second generation of Sensity 2. The lens adopts the patented design of Stabilight Technology™ to ensure that the lens has a stable discoloration performance in any climate or season, bringing a convenient and comfortable vision experience all-weather. Hoya's photochromic technology started late, but its strong scientific research capabilities have developed a photochromic lens technology that can compete with Transition. Sensity's photochromic lens reacts quickly to photosensitivity and color change, and its color reversion performance is also rapid and excellent.
Hoya - AS SENSITY 2 Photochromic lens from $2199
We did a simple test for the Transitions Acclimate and the Transitions T7
The clear and transparent state of the two is only maintained for less than 1 second, and the darkest color has been reached in about 20 seconds. Transition T7 is very close to the dark color of ordinary sunglasses.
It takes about 30 seconds for mainstream photochromic lenses to turn dark, while it takes about 2 minutes for the lenses to become transparent. Under normal daily use, the design life of the photochromic lens is about 2 years. Aging photochromic lenses will slow down the speed of discoloration, etc., and become "sunglasses" when they are worn indoors for a long time. If your full-sight lens fails to become transparent in the room for a long time, you should consider changing the lens.
The introductory footage by Essilor for Transitions lenses clearly shows the benefits of photochromic lenses in daily use. The color depth of the color changing lens will change with the light and darkness of the environment, providing the most comfortable luminosity for the eyes.
