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Do Photochromic Lenses Work In A Car?

Meta Description: Photochromic lenses don't get dark when us...

Meta Description: Photochromic lenses don't get dark when used in cars due to the windshield technology. This post explains all you need to know about car windshield technology and your photochromic lens.


Do Photochromic Lenses Work In A Car?


Most Photochromic lenses do not darken inside cars. Therefore the simple answer is no. However, there are some exceptions that will be discussed later in this article.

In order to understand why your photochromic lenses do not darken inside your car, we will start by explaining what a photochromic treatment does to your lenses.

Photochromic lenses are made up of particles sensitive to ultraviolet rays, therefore, they darken or lighten depending on the amount of UV rays your lenses absorb. Thus; If you are in a closed space or with artificial light, your glasses will have “clear” lenses; if you go outside and are exposed to the Sun, they will darken to a deep hue in a short period of time.

That said, photochromic lenses are not entirely recommended for driving since the windshields of most cars for a couple of years now have a UV light filter integrated from the factory to reduce glare for drivers on the road.


How photochromic Glasses work in the Car

Your windshield is normally very different from the rest of your glass, in that it is two laminated panes with a layer of plastic that contains UV light inhibitors that protect the plastic and therefore also prevent UV light transmission. A laminated glass windshield typically blocks 98 to 99% of all UV rays.

Ultraviolet light operates under the visible spectrum and is invisible to the human eye. Its presence and effect have nothing to do with the luminosity of the sun; This is why you can still get sunburned if you go to bed on a cloudy day. This sometimes leads to confusion about the effectiveness of transition lenses and fuels questions such as;

"If bright sunlight shines into my car, why don't my photochromic lenses darken? Are they defective? "


No, your photochromic lenses work very well. They simply cannot react to a light source that is not present, and in a vehicle, most of that UV light has already been taken out of the equation. Additionally, the lenses transmit light at about 83% when indoors (without anti-reflective coating).



‘My Photochromic Lenses sometimes darken in the car and sometimes do not’

You may notice your lenses darkening in your car. This is because, in typical automotive vehicles, only the windshield blocks a high percentage of ultraviolet rays. Side and rear windows are rarely laminated. Therefore, although they have some anti-UV properties, they also allow a good portion of ultraviolet light to escape. And, of course, open windows allow certain amounts of ultraviolet light to filter in which can make your transition lenses react.


How do I Use Photochromic Lenses while Driving


Photochromic lenses are considered useless when driving during the day. This is because it doesn’t serve its purpose of blocking UV rays when inside the car as the windshield already does that. 

Therefore, If your prescription photochromic lenses don't darken enough for your comfort level in the car, you have options. You can purchase a pair of prescription sunglasses for driving. You can also purchase clip-on sunglasses to temporarily attach to your prescription glasses.


How Can Photochromic Lenses Be Beneficial For Driving?

If your windshield is defective or broken, it can impair its ability to block most UV rays from getting to your eyes.


 Therefore, you can use a photochromic lens in the meantime before you find a solution to your windshield. It’s not advisable to drive around with a defective windshield just because you have a photochromic lens though as there are other concerns.

Photochromic lenses can also be beneficial if you love driving with your windows down. This can help prevent the adverse effects of UV rays when you look outside through your car window.

Lastly, most people don’t know the amount of UV rays escaping through their windshield. Therefore, a photochromic lens can still be worn just in case. Photochromic lenses can also help to block blue light while driving, especially lenses produced by Maat Optical.


In Conclusion



Photochromic lenses have limited use when driving and may even be totally not needed. However, they can be used in some few conditions and can even be very beneficial in other situations. Therefore, the decision to use a photochromic lens while driving is an individual decision. 

If you would like a photochromic lens that works behind the wheel, consult Maat Optical. We have over 20 years of experience dedicated to satisfying the photochromic lens needs of all our customers. Photochromic lenses produced at Maat Optical have faster responsiveness, get dark up to CAT-3 levels, stability and consistency in all colors and a long lifespan.  




Are Photochromic Lenses Good For The Eyes?

Photochromic lenses adapt to changing light, reduce glare and limit UV exposure, making them a great choice for eye protection.


How Do Photochromic Lenses Work?

Photochromic lenses contain special molecules called organic photochromic dyes. When exposed to ultraviolet (UV) light, these molecules undergo a chemical reaction, causing a change in the lens color. In the absence of UV light, the molecules are transparent. Upon UV exposure, they undergo a structural change, absorbing certain spectra and darkening the lens color. As light diminishes or UV light is no longer present, the molecules revert to their original state, gradually returning the lens to a transparent condition. This automatic adjustment feature allows photochromic lenses to provide appropriate sun protection under varying light conditions, offering comprehensive eye care.


Jay Zhang

Jay Zhang, with over 5 years of experience, currently serves as the Sales Manager at JIANGSU MAAT OPTICAL TECHNOLOGY CO LTD. He specializes in research and development, as well as manufacturing, of photochromic lenses with a wide range of optional colors. In his role, Jay excels in marketing, customer-focused service, ensuring service quality, and enhancing the overall customer experience. His expertise lies in the commerce sector, contributing to the success of the company in the dynamic Chinese market since January 2023.

Learn More About Jay Zhang

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