How to Tell if Your Sunglasses Are Real UV400 Protection or Fake

November 06, 2025

How to Tell if Your Sunglasses Are Real UV400 Protection or Fake

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Not All Sunglasses Protect Your Eyes

Just because sunglasses are dark doesn’t mean they’re safe. Some cheap or fake pairs look stylish but provide little to no UV protection, leaving your eyes vulnerable to harmful rays. Real UV400 sunglasses block 100% of UVA and UVB light — the gold standard for eye safety. Here’s how to tell if your shades actually deliver the protection they promise.

☀️ What “UV400” Really Means

The term UV400 means that the lenses block all light rays with wavelengths up to 400 nanometers, including both UVA (aging rays) and UVB (burning rays).
This level of protection ensures that zero ultraviolet light reaches your eyes.

Without it, UV rays can lead to:

Cataracts
Macular degeneration
Eye sunburn (photokeratitis)
Premature wrinkles around the eyes

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🧠 1. Check for a UV400 Label or Certification

Legit sunglasses will have a sticker, tag, or engraving indicating UV400 or “100% UV Protection.”
Look for:

“UV400” printed on the inside of the arm
A manufacturer’s guarantee on packaging
CE or ANSI certification marks (especially in professional eyewear)

If there’s no UV mention anywhere, it’s a red flag.

🔬 2. Test Them with a UV Light Tester

Some optical stores and online retailers offer UV testers that measure how much UV passes through your lenses.
If you have access to one, hold the sunglasses between the light source and the detector — UV400 lenses will block nearly all light.

Pro Tip: Many optometrists will test your lenses for free.

🕶️ 3. Avoid the “Dark Lens Trap”

Dark lenses without UV filters are actually worse than wearing none at all.
Why? Because your pupils dilate in the shade — allowing more UV rays to enter unfiltered.

So if you’re buying cheap shades, make sure they specifically list UV400 protection, not just “fashion lenses.