March 23, 2020

Photochromic Lenses 101

You might know them better as transitions, reactions, adaptives, or even reactolights, but whatever you call them, we’re calling them out as one of the optical industry’s most significant inventions!

Imagine being able to wear glasses with lenses that automatically darken when you go outside, and lighten up again when you return indoors. Well, that’s exactly what photochromic lenses do. To be fair, they’ve been around since the early 1960s and yet, even now, most wearers know little about the way they work nor of their many benefits.

Take our crash-course – a kind of ‘Photochromic Lenses 101’ – and get those questions answered!

First things first… what are photochromic lenses?

Photochromic lenses (also known as photochromatic lenses) rely on a chemical treatment of the lenses where the chemicals react to ultra-violet (UV) rays and blue light and change colour – darkening on exposure to light and becoming neutral when not exposed. This entire process of lens darkening can happen within 60 seconds… and when you come indoors from the sun they’ll return to an almost clear state within two minutes, and usually be fully clear in around five minutes.

What are the benefits of photochromic lenses?

Mainly, they make it easy for you to ensure your eyes are afforded a high level of protection from ultra-violet and blue light. Why do they make it easy? Because, when exposed to higher levels of UV and blue light, they automatically darken to block out more of the rays.

Sunlight contains UV and blue light. UV light is part of the non-visible light spectrum and we are exposed to it every day when we’re out in the daytime. Blue light, which is part of the visible light spectrum, reaches deeper into the eye and its cumulative effect can cause damage to the retina.

The eyes’ natural blockers are pretty ineffective against blue light! While the cornea and lens of the eye are better at blocking UV rays from reaching our light-sensitive retinas, almost all visible blue light passes through these barriers, which could reach and damage the delicate retina.

Ultra-violet rays are present in the environment all the time, so lenses that are given the photochromic treatment protect your eyes from not just the brightness of the sun, but also from invisible and potentially harmful UV rays.

In fact, photochromic lenses darken whenever they are exposed to UV light. UV light is present even on cloudy days because these rays can penetrate through the clouds. So, your photochromic lenses will darken when required, further protecting your eyes from UV and blue light damage, including early onset cataracts and other eye problems.

On a practical note, you might find you only need one pair of glasses! No more carrying both your glasses and sunglasses wherever you go… switching back and forth each time you go outside and then head back in. Photochromic lenses provide the potential for a two-in-one eyewear solution!

Glasses with photochromic lenses are suitable for wearers of all ages, a clear advantage especially with children under the age of 12 who are more vulnerable to sun damage due to the fact that their eyes’ natural protective barriers are still underdeveloped.

Are photochromic lenses good for my eyes?

Yes! Very much so! The basic premise of photochromic lenses is that that are designed to block UV and blue light. These types of light are not your eyes’ friend! Eye protection matters! UV radiation from the sun can damage not only the skin of your eyelid but also the cornea, lens and other parts of the eye. Blue light from the sun (as well as fluorescent lights and some computer screens) can lead to deep eye damage. For the long-term problems that result from light damage – cataracts, pterygia, pingueculae, macular degeneration – there is no way to reverse what’s already happened. A photochromic lens isn’t the only way to protect your eyes though – a pair of high-quality sunglasses will offer UV-A and UV-B, and other lenses are available with blue light protection too!

What is the difference between photochromic lenses and transition lenses?

Well, on one hand, there’s no specific difference, and on another, there’s a world of a difference! Transition lenses, or rather ‘Transitions® Lenses’ as the manufacturer would prefer everyone thought of them, are a brand of photochromic lenses – the most well-known, the market leader and, probably the best! The name ‘transition’ is used by some, rather lazily, to refer to any and all photochromic lenses in much the same way all vacuum cleaners became known as ‘hoovers’… even when they weren’t! So, beware… you might not be buying real ‘Transitions® Lenses’ unless you ask!

Transitions® Lenses didn’t become the market leader by accident. Rather, it was by design.   They offer fashion color lenses, perfect for the trendsetter who wants it all. Beyond the better-known brown and grey lenses, Transitions® offers photochromic lenses in sapphire, amber, amethyst, and emerald green… all exclusive at MAGRABi.

Photochromic Lenses: Pros & Cons (the photochromic cheat sheet!)


  • Photochromic lenses are convenient, and can be worn under most circumstances, whether indoors or out.
  • Photochromic lenses offer continuous UV ray and blue light protection.
  • Photochromic lenses can be manufactured to meet the requirements of most prescriptions.
  • Photochromic lenses are available in many styles and colors,
  • If you need shatter-resistant lenses, bifocals, progressives or have other specific needs, there’s almost certainly a photochromic lens for you.
  • One pair of photochromic lens-fitted glasses are half as likely to get lost as a pair of prescription glasses and a pair of sunglasses!


  • Photochromic lenses darken and lighten to varying degrees depending on the brand. Some also take longer to change than others. Discuss your needs and options with an eyecare professional.
  • Photochromic lenses can take longer to adjust in cold weather – meaning they take a bit longer to react to UV rays in winter.
  • Not all photochromic lenses darken well inside cars. Auto glass has some UV protection, which can prevent photochromic lenses from darkening. Some lenses are designed to help solve this problem.

Today’s advanced, high-quality eyeglasses with photochromic lenses are a sensible solution for many people. With protection ‘always on’, they block 100% of UV and protect from harmful blue light. Isn’t it about time you considered whether they’re a good fit for your lifestyle?

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