Sunglasses and UV Protection: What You Need to Know

Bangladesh gets intense sun for most of the year, so UV protection is not a nice-to-have. It is the main job of your sunglasses. The problem is that dark lenses can make you believe you are protected when you are not.

UV-A and UV-B in simple terms

UV-A and UV-B are the two bands of ultraviolet light that reach your eyes. Over years of exposure, both can damage the lens and the retina and speed up cataract formation. Sunglasses should block 100% of both, usually marked as UV400.

Why dark lenses can be dangerous

When lenses are dark, your pupils open wider to let in more light. If that dark lens does not block UV, you are letting more harmful radiation reach the back of your eye than you would with no sunglasses at all. This is why cheap, unmarked sunglasses are genuinely risky.

What to look for

• UV400 marking, which blocks UV-A and UV-B up to 400 nanometres
• Polarised lenses for glare, especially while driving or near water
• A snug fit that prevents light entering around the edges
• Larger frames or wraparounds for broader coverage

Polarisation is separate from UV

Polarised lenses reduce glare from flat surfaces like roads, water and windows. That is comfort and clarity, not protection. A lens can be polarised and still fail UV protection, so check both features independently.

Buying from a reputable brand or a trusted local optical store in Bangladesh usually guarantees the UV rating. When in doubt, ask for the UV400 specification in writing before you pay.