Photochromic lenses are eyeglass lenses that are clear (or nearly clear) indoors and darken automatically when exposed to sunlight. Other terms sometimes used for photochromic lenses include “light-adaptive lenses,” “light intelligent” and “variable tint lenses.”
Anyone who wears glasses knows what a hassle it can be to have to carry around separate prescription sunglasses when you are outside. With photochromic lenses people can easily adapt to the transition from artificial (indoor) to natural (outdoor) lighting while providing UV protection as well, they eliminate the need for prescription sunglasses.
An added benefit of photochromic lenses is that they shield your eyes from 100 percent of the sun’s harmful UVA and UVB rays
How photochromic lenses work
The molecules responsible for causing photochromic lenses to darken are activated by the sun’s ultraviolet radiation. Because UV rays penetrate clouds, photochromic lenses will darken on overcast days as well as sunny days.
Because a person’s lifetime exposure to sunlight and UV radiation has been associated with cataracts later in life, it’s a good idea to consider photochromic lenses for children’s eyewear as well as for eyeglasses for adults.
Adding anti-reflective coating to photochromic lenses enhances their performance even further. AR coating allows more light to pass through photochromic lenses for sharper vision in low-light conditions (such as driving at night), and eliminates bothersome reflections of sunlight and other light from the backside of the lenses in bright conditions.
Though photochromic lenses cost more than clear eyeglass lenses, they offer the convenience of reducing the need to carry a pair of prescription sunglasses with you everywhere you go.
At Hopesun, photochromic lenses are available in nearly all lens materials and designs, including high-index lenses, bifocals and progressive lenses.
If you value quality, performance and innovation you’ve come to the right place.
Material | NK-55 | Polycarbonate | MR-8 | MR-7 | MR-174 |
Refractive Index | 1.56 | 1.59 | 1.60 | 1.67 | 1.74 |
Abbe Value | 35 | 32 | 42 | 32 | 33 |
Specific Gravity | 1.28g/cm3 | 1.20g/cm3 | 1.30g/cm3 | 1.36g/cm3 | 1.46g/cm3 |
UV Block | 385nm | 380nm | 395nm | 395nm | 395nm |
Design | SPH | SPH | SPH/ASP | ASP | ASP |
● SV 1.56 Photochromic
● SV 1.59PC Photochromic
● SV 1.60 Photochromic
● SV AS 1.67 Photochromic
● SV AS 1.74 Photochromic
● BF 1.56 Photochromic
● BF 1.59PC Photochromic
● PRG 1.56 Photochromic
● PRG 1.59 PC Photochromic