Photochromic lenses have been around since the 1960s. Popularly known as “transition lenses,” these specialized lenses adapt to different shades of light. When you’re indoors, photochromic lenses are clear—or close to it—and they darken on their own when exposed to sunlight.
Don’t confuse transition lenses with progressive lenses. Progressives contain multiple, graduated prescriptions in one lens, to help you see well at different distances.
Photochromic lenses can contain a progressive lens prescription if needed, or a bifocal or single prescription. But, they can also be non-prescription too.
Photochromic lenses are certainly convenient, but like any eyewear, they aren’t for everyone. Let’s first examine how they work, and then discuss the pros and cons of photochromic lenses.
How Do Photochromic Lenses Work?
Photochromic lenses have a light-sensitive coating on them. When exposed to the sun’s UV rays, molecules in the coating change their shape and structure, allowing them to absorb visible light and darken.
Even when the sun isn’t shining, photochromic lenses might darken because UV rays penetrate cloud cover. But, they don’t always darken to their final sunglass form during high-glare activities like boating or skiing. So if you’re someone who is light-sensitive, they might not be the right option for your eyes.
Some people swear by their photochromic lenses. If you’re wondering if they’re right for you, read on:
Pros of Photochromic Lenses
UV Protection
UV rays can do plenty of damage. Between 5% and 10% of skin cancer is eyelid skin cancer. Other types of cancer near the eye can also occur from too much sun exposure. Without UV protection, your risk of other eye diseases increases too.
Photochromic lenses almost always have UV protection to shield your eyes from the sun’s rays.
Endless Options
Years ago, photochromic lenses were only available in grey. Now, they come in colours like ambers, browns, and greens too. Sleek classic lines, trendy cat-eye frames, or the always-cool aviator style can contain photochromic lenses.
So, whatever fashion statement you want to make, you can do it with photochromic eyewear. The lenses are also available in prescription or non-prescription varieties. If you need bifocals, trifocals, or progressive lenses, you can get them in photochromic varieties too.
Convenience
For prescription eyewear users, carrying glasses and sunglasses wherever you go and scrambling to switch between them is a familiar event. Photochromic lenses make it possible to have a two-in-one solution.
If you’re someone who misplaces your glasses regularly or forgets your sunglasses at home, it can be a lifesaver to have just one pair of eyewear to keep track of. With photochromic lenses, you won’t need that second set of specs to search for.
Cost Savings
A single pair of eyewear is great if you’re on a budget. Photochromic lenses might save you from having to invest in a pair of prescription sunglasses. You can just have a single piece of eyewear for all sun conditions.
When it comes time to replace your eyewear or update your prescription, you’ll just be replacing one pair, not sunglasses and regular glasses at the same time.
Cons of Photochromic Lenses
Temperature Fluctuations
The temperature impacts the rapidity of shade changes in photochromic lenses. During extreme heat, they may not achieve full darkness and in colder temperatures, they might take extra time to return to a clear state.
Molecules move slower in the cold so the delay in shade shift during winter weather is due to the slower shape-changing of the coating’s molecules.
Reaction Times
Photochromic lenses adjust to your surroundings relatively quickly, though the slight delay can be bothersome. The time it takes lenses to change shade depends on temperature, brand, age, and amount of UV exposure.
Normally, it takes the lenses about 30 seconds to darken and 5 minutes or less to return to their clear state once indoors. If you go back and forth between outdoor and indoor environments throughout the day and require rapid change, photochromic lenses might not be for you.
Difficulty Driving
The windshield of your car can block the UV light needed to begin the chemical process that changes the shade of your photochromic lenses. So, while you can certainly drive in them, they might not help limit sunlight while you do so.
Wear & Tear
Over time, photochromic lenses become less effective. They generally last around 3 years before they lose their ability to darken when exposed to UV light.
So, Should I Get Photochromic Lenses?
As with any eyewear decision, it’s important to talk with your optometrist about the options. They’ll discuss your lifestyle and needs with you and help you select the choice for your unique situation.
As an eyewear enthusiast with a deep understanding of optical technology and advancements, I can confidently provide insights into the concepts discussed in the article about photochromic lenses. My expertise is rooted in a comprehensive knowledge of lens technologies, their applications, and the evolving trends in the eyewear industry.
Photochromic Lens Technology: Photochromic lenses have indeed been a game-changer since the 1960s. These lenses, commonly known as "transition lenses," incorporate a light-sensitive coating. This coating reacts to the sun's UV rays, causing molecules within it to change shape and structure. This alteration enables the lenses to absorb visible light, resulting in a darkening effect. It's worth noting that even in the absence of direct sunlight, these lenses may darken due to UV rays penetrating cloud cover.
Distinguishing Photochromic from Progressive Lenses: It's crucial to differentiate between photochromic lenses and progressive lenses. Unlike progressives, which incorporate multiple prescriptions for different distances into a single lens, photochromic lenses can accommodate a variety of prescriptions, including bifocal or single prescriptions. Moreover, photochromic lenses are available in both prescription and non-prescription forms.
Pros of Photochromic Lenses:
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UV Protection: Photochromic lenses almost always include UV protection. This is essential in preventing damage from UV rays, which can contribute to skin cancer around the eyes and other eye diseases.
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Endless Style Options: Unlike the limited grey options in the past, photochromic lenses now come in various colors, allowing wearers to express their fashion preferences. Whether classic or trendy frames, these lenses cater to diverse styles.
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Convenience: Particularly advantageous for prescription eyewear users, photochromic lenses eliminate the need for separate glasses and sunglasses. This two-in-one solution simplifies eyewear management, making it especially beneficial for those prone to misplacing or forgetting their glasses.
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Cost Savings: Investing in a single pair of eyewear with photochromic lenses can save money, as there's no need for a separate pair of prescription sunglasses.
Cons of Photochromic Lenses:
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Temperature Fluctuations: The speed of shade changes in photochromic lenses can be affected by temperature. Extreme heat may hinder full darkening, while cold temperatures might slow down the return to a clear state.
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Reaction Times: Though relatively quick to adjust, the reaction time of photochromic lenses depends on various factors, including temperature, brand, age, and UV exposure.
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Difficulty Driving: The UV-blocking windshield in cars can impede the chemical process that triggers the darkening of photochromic lenses, potentially limiting their effectiveness while driving.
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Wear & Tear: Over time, photochromic lenses may lose their effectiveness, typically lasting around 3 years before diminishing in their ability to darken when exposed to UV light.
In conclusion, the decision to opt for photochromic lenses should be made based on individual preferences, lifestyle, and specific eyewear needs. Consulting with an optometrist is essential for personalized advice tailored to one's unique situation.
