What are photochromic lenses?

Photochromic lenses automatically adapt to changing light conditions. When indoors photochromic lenses will be clear and when outdoors and exposed to sunlight will darken automatically. Photochromic lenses are also known as light-adaptive lenses or light intelligent lenses.

When photochromic lenses are exposed to UV light, the molecules in the lens change and cause the lenses to darken. This can provide optimal visual comfort and protection when you need it most. Photochromic lenses can still darken even on overcast days because UV light can penetrate the clouds making sure you’re receiving optimal UV protection. Most photochromic lenses typically won’t darken in the car as windshields block most UV light. At Essilor, we offer photochromic lenses that darken behind a windshield as well as a full range of photochromic lenses with different benefits and capacities.

How do photochromic lenses work?

Photochromic lenses have billions of molecules inside the lens that cannot be seen. When the lenses are not exposed to UV light, these molecules stay in their usual structure, and the lens remains clear. If they're exposed to UV light, the molecule structure has a chemical reaction and changes shape; this activates the lens into a uniform tinted state. Once your glasses are out of the sunlight, the molecules revert to their usual form, and the lenses are clear again.


Photochromic lenses will instinctively and seamlessly adapt to changing light, adjusting to the perfect tint depending on brightness. This is incredibly convenient for a spectacle wearer as it offers an on-the-go solution if you spend a lot of time going from indoors to outside.

Wearing photochromic lenses can offer sufficient protection from the sun, which is crucial to maintaining healthy vision. With fast and responsive technology, photochromic lenses protect your eyes from harmful light including UV light and Blue-Violet light.


Photochromic lens is the term given to a type of lens that will automatically change tint according to the light conditions. Transitions is a brand of photochromic lenses. At Essilor, we offer a range of Transitions photochromic lenses, created with the latest technology. This includes fast fade back, a choice of colours and enhanced colour perception, visual protection and comfort.


Photochromic lenses adapt to the changing light so that your eyes don’t have to. By wearing this type of lens, you can help your eyes to relax a little more.

It has been shown that overexposure to UV light and blue-violet light can contribute to health conditions like cataracts and age-related macular degeneration(1). By wearing adequate protection, you can reduce this risk(2). Photochromic lenses are a helpful daily solution because they protect your eyes automatically.


Vehicle windshields block most UV light meaning standard photochromic lenses will not activate to a darkened tint even when you’re driving in bright sunlight. However, new technology has allowed for some photochromic lenses to respond and activate with just visible light.

Transitions XTRActive are the first photochromic lenses to activate behind a windshield, meaning they are the perfect lens solution when driving. You are able to combine your corrective lens design with this advanced light intelligent technology, resulting in optimum visual comfort and protection.

Can I have photochromic varifocal or single vision lenses?

Yes! The photochromic lens technology is inside your lenses and will not affect the lens correction. This means you can have varifocal photochromic lenses or single vision photochromic lenses. It also means you can have photochromic lenses even if you do not have a glasses prescription. 

If you're presbyopic, Transitions light intelligent technology is available with Varilux X series, Varilux E series, Varilux Physio 3.0, Varilux Comfort Max and Varilux Road Pilot. If you need lenses to correct your short-sightedness or long-sightedness, you can have Eyezen single vision lenses with Transitions technology.

Simply put, your lenses are made up of three parts. The eyesight correction part (varifocal/single vision), the protective eye health technology inside the lens (photochromic/polarised) and finally, the lens protection and visual clarity enhancement (a lens coating). 

Not sure what lenses are best for you? Speak to your local optician, they will be able to determine the best lens solution for your lifestyle and eyesight needs.


(1) McCarty CA, Taylor HR. A review of the epidemiologic evidence. linking ultraviolet radiation and cataracts. Dev Ophthalmol. 2002; 35:21-31. Sunlight and the 10-year incidence of age-related maculopathy: The Beaver Dam Eye Study. Arch. Ophthalmol., 122, 750-757. New discoveries and therapies in retinal phototoxicity, Serge Picaud et Emilie Arnault, Points de Vue N°68, Spring 2013.

(2) Eye health relies on various factors (age, genetic, smoking, diet …). Light is one of the modifiable risk factors on which an ophthalmic lens may act.