Many people think these terms mean the same thing, but they don't.
UV400
UV400 lenses block nearly all UVA and UVB rays up to 400 nm, helping protect your eyes from harmful ultraviolet radiation.
Polarized
Polarized lenses reduce glare reflected from flat surfaces like roads and water, making vision more comfortable in bright conditions.
Which Should You Choose?
Ideally, choose sunglasses that provide both UV400 protection and polarization for maximum comfort and eye protection.