Wednesday, June 16, 2010

More on Sunglasses--Visible Light Transmission

It's a beautiful, bright sunny day in Cleveland, Ohio! We don't get too many of these for most of the year, but Spring and Summer around here can be magnificent. Let's talk about another thing that you should think about when you are choosing what sunglasses to wear, how dark should your sunglasses be.

The technical term for this choice is "Visible Light Transmission". When Eye Doctors and Opticians think about sunglasses we think about how much light actually gets through, the VLT. It's funny because when we talk about UV protection we talk about how much UV light DOESN'T get through. With VLT the darker the lens the lower the VLT in general. But sunglass lens technology has become so advanced that some relatively light lenses actually block out lots of visible light!

Your activity and your environment will help you choose your sunwear. Let's think about Cleveland for a minute. Right now it's pretty sunny. We're a lake community with Lake Erie just to the north of everyone and everything. Lake activities make you want POLARIZED sunglasses, and today you would look for something that has around 20% VLT. Two super examples would be the Nike Brown (16% VLT) or Grey (17% VLT) Max Tint Polarized lenses.

Now, it IS Cleveland, and we get lots and lots of cloudy, overcast days around here. On days like that it's not so important that you wear polarized sunglasses, but you could if you wanted. On cloudy days you want UV protection, decreased transmission of blue light waves, and a slightly higher VLT, usually around 40%. Good choices from Nike would be the Max Tint Orange (60% VLT) or Smoke (50% VLT). We often see Dr. White with his Max Tint Orange Nikes on cloudy days.

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