Frequently Asked Questions About Photochromic Glasses
General Questions
What are photochromic glasses?
Photochromic glasses feature special lenses that automatically darken when exposed to UV light (typically outdoors) and return to clear when UV exposure decreases (typically indoors). This technology eliminates the need to switch between regular glasses and sunglasses.
How do photochromic lenses work?
These lenses contain millions of photochromic molecules that change structure when exposed to UV radiation. When the molecules change shape, they absorb more light, causing the lenses to darken. When UV light is no longer present, they return to their original form, and the lenses become clear again.
Are “transition lenses” the same as photochromic lenses?
Yes, “Transitions” is actually a popular brand of photochromic lenses. Many people use the term “transition lenses” generically, similar to how “Kleenex” is often used to describe any facial tissue.
How long do photochromic lenses take to change?
Most modern photochromic lenses begin darkening within 30 seconds of UV exposure and reach their fully darkened state within 2-3 minutes. When returning indoors, they typically take 3-5 minutes to completely clear, though this varies by brand and environmental conditions.
Performance Questions
Do photochromic glasses work in cars?
Most car windshields block UV rays, which means traditional photochromic lenses won’t activate fully while driving. However, newer generations of photochromic technology (like Transitions XTRActive) can respond to both UV and visible light, allowing them to darken behind car windows.
How dark do photochromic lenses get?
The darkness level depends on the brand, lens material, and environmental conditions. Most photochromic lenses block 70-85% of visible light at their darkest state, which is comparable to medium-dark sunglasses. Specialty outdoor photochromic lenses can block up to 90-95% of visible light.
Does temperature affect how photochromic lenses work?
Yes. Photochromic lenses typically get darker and stay dark longer in cold weather. In hot conditions, they may not darken as much and clear more quickly when you go back inside.
Do photochromic lenses block 100% of UV rays?
Yes, even in their clear state, quality photochromic lenses block 100% of UVA and UVB rays, providing full UV protection for your eyes.
Practical Considerations
How long do photochromic lenses last?
The photochromic molecules gradually wear out over time. Most photochromic lenses maintain good performance for 1-3 years, after which their ability to darken may diminish. The exact lifespan depends on usage, exposure to extreme temperatures, and the specific brand.
Can I get photochromic lenses with my prescription?
Yes, photochromic technology can be incorporated into nearly all prescription lens types, including single vision, bifocal, progressive, and high-index lenses.
Are photochromic glasses good for driving?
Traditional photochromic lenses aren’t ideal for driving because car windshields block the UV light needed to activate them. For driving, consider specialized photochromic lenses that respond to visible light (like Transitions XTRActive) or dedicated prescription sunglasses.
Can I get photochromic lenses in different colors?
Yes, most manufacturers offer photochromic lenses in gray, brown, and sometimes green. Gray provides the most natural color perception, brown enhances contrast, and green offers a balance between the two.
Cost and Care
How much more expensive are photochromic lenses?
Photochromic lenses typically cost $100-$400 more than regular prescription lenses, depending on the brand, lens material, and any additional features (like anti-reflective coating). However, many people find the convenience worth the investment since they’re essentially getting two pairs of glasses in one.
Does insurance cover photochromic lenses?
Many vision insurance plans provide partial coverage for photochromic lenses as an “upgrade” option. Coverage varies significantly between providers, so check your specific plan details.
How should I clean and care for my photochromic glasses?
Care for photochromic glasses just as you would regular glasses:
- Clean with lens cleaner and a microfiber cloth
- Avoid extreme heat, which can damage the photochromic molecules
- Store in a case when not in use
- Don’t leave them on your car dashboard, where heat can degrade the photochromic properties
Do photochromic lenses scratch easily?
The scratch resistance depends on the lens material and coatings, not the photochromic technology itself. Most photochromic lenses come with scratch-resistant coatings, but no lens is completely scratch-proof.
Special Applications
Can children wear photochromic glasses?
Absolutely! Photochromic glasses are excellent for children since they automatically provide UV protection outdoors, and children may not be reliable about switching between regular glasses and sunglasses.
Are photochromic lenses available for contact lenses?
Yes, there are photochromic contact lenses available, though the selection is more limited than with glasses. Acuvue Oasys with Transitions is a popular option.
Can I get photochromic lenses in my computer glasses?
Yes, though be aware that computer screens emit very little UV light, so photochromic lenses won’t darken significantly indoors under normal lighting conditions. Some people prefer to combine photochromic technology with blue light filtering for computer glasses.
Are there photochromic options for people who don’t need prescription glasses?
Yes, many manufacturers offer non-prescription photochromic sunglasses and “plano” (non-corrective) photochromic glasses that can be worn purely for the UV protection and light-adaptive benefits.