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What Are Photochromic Lenses?

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A man wearing eyeglasses with photo-sensitive lenses that auto-darken when comes into contact with UV light.

Whether basking in the summer sun or driving through the winter rush hour on your way home, excessive UV ray exposure can increase your risk of several eye conditions and diseases—some of which may contribute to vision loss. As such, many of us turn to sunglasses to protect our vision during these particularly bright days.

But what if you don’t want to carry a second pair of eyeglasses? What if you don’t have the space to keep them on you at all times? What if purchasing a second pair of frames isn’t in your budget? A great alternative is photochromic lenses

Photochromic lenses—or transition lenses—are clear lenses that darken when exposed to UV light. In this article, we’ll look at how these lenses work, their potential benefits, and how you can combine them with other eyeglass materials and treatments to help keep your vision clear and comfortable. 

If you’re interested in getting your own pair of photochromic lenses, book an appointment at Orillia Optometry today!

Benefits of Photochromic Lenses

Before we look at how these lenses work, let’s consider how they can serve your vision and eye comfort by discussing some of the most common reasons why people turn to photochromic lenses.


Probably the most common reason many turn to photochromic lenses is their convenience. These lenses eliminate the need to carry a pair of sunglasses wherever you go, making it easy to enjoy the outdoors without worrying about UV exposure.

Photochromic lenses change shades on cloudy days because they can detect UV rays that penetrate clouds.


Keeping a few different pairs of glasses on hand is a great idea if you want to change your look to match a new outfit. 

However, if you’re looking to keep your eyewear budget low, photochromic lenses give you sunglasses and regular glasses in one cost-efficient package.

All-Day Comfort & Protection

Photochromic lenses can constantly adapt to your environment to protect your eyes, whether on the beach in the summer heat, at a job site in the middle of a bitter winter, or driving your kids to school. Photochromic lenses can also protect your eyes from blue light, a type of UV light that may contribute to various eye strain symptoms.

And just like sunglasses, they can help reduce your risk of developing conditions and diseases related to excessive sun exposure, like:

  • Cataracts
  • Macular degeneration
  • Skin cancer around the eyes
A man's hand holding sunglasses with black frames and photochromic lenses in the garden.

How Do Photochromic Lenses Work?

Now that we’ve looked at why you might want to pick up a pair of these lenses, let’s look at how they work. Ready for a quick science lesson?

The darkening process starts at the molecular level. Each photochromic lens is built with silver halide and chloride compounds that chemically change structure when they come into contact with UV light. When UV light passes through the lens, trillions of molecules simultaneously change the tint of the lens to block UV light.

Scientists have worked on this technology since it was introduced to the public in the 90s, improving the speed at which the lenses change shade while also bringing the same great benefits to contact lens wearers.

Personalizing Your Eyewear

While photochromic lenses are great for protecting your eyes from harmful UV rays, they are only one small characteristic of your eyeglasses. To make the most of your eyewear, speak to our optical team to see how we can help personalize your specs to help support your vision and quality of life.

For example, we might have you:

Look at Different Frame Materials

There is a wide variety of frames materials on the market, but some might be better suited for your lifestyle than others. Some common materials we may recommend include metals like titanium, monel, or aluminum and plastics like zylonite or blended nylon.

Consider a Few Different Lens Treatments

Depending on your vision and eye care needs, we can recommend specific lens coatings or treatments to serve your eye comfort and vision better. We can combine photochromic lenses with:

  • Anti-reflective coating
  • Anti-scratch coating
  • Anti-fog coating

Update Your Prescription

The best way to ensure you’re getting the clearest vision is to have regular eye exams and update your prescription.

Ready to Upgrade Your Lenses?

By getting prescription photochromic lenses, you can enjoy your sight every day without interruption. Learn more about photochromic lenses when you come in for an appointment, or visit our optical gallery to see how we can combine your favourite frames with these innovative lenses today!

Dr Moore

Written by Shawn Moore

Dr. Moore began his career in Barrie, moved to Orillia, and purchased what is now Orillia Optometry in 2001. Dr. Moore thoroughly enjoys primary care optometry, but his areas of interest are vision therapy, concussion management, contact lenses / multifocal contact lenses, and dry eye.

More Articles By Shawn Moore
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