Spectrophotometry and the Science of Sunglasses

We all know what happens to our skin when we fall asleep at the beach or go for a long walk on a sunny summer day but what about our eyes? Sun damage is not something that can only happen to our skin. Studies have shown that our eyes are just as susceptible, if not more susceptible to damage from the sun’s UV rays. Prolonged unprotected exposure to UV rays can burn the surface of the eye, and has been linked to the development of other serious eye conditions. Fortunately, protecting your eye is incredibly easy. All it takes is a minimal amount of advanced planning and a good pair of sunglasses.

Biologically, our eyes seem well protected; they are set back in our skull, have eye brows, eye lids, and lashes to try and keep the sensitive parts of the eye-covered, but under extreme or prolonged exposure it’s not enough protection from UV damage. Good sunglasses will have lenses that will block UV ray entirely, but not all sunglasses are created equal. Some brands are good for driving or light use but in extreme conditions like on the beach or in snow where reflective sunlight is very intense they may not provide adequate eye protection.

UV VIS spectrophotometry is often used to determine the level of UV protection that sunglasses provide. By shining UV rays through the lenses, a spectrophotometer then measures the amount of UV rays that come through. In fact, Professor Liliane Ventura has used data from her research with UV rays to create a machine that will provide shoppers with real time feedback about the level of protection their sunglasses are giving them. All consumers have to do is place their glasses in the machine and it will provide them a report about the level of protection and settings where the glasses they selected will be most beneficial.

Since as of right now there is only one machine like that in the whole world, one way to make sure you get adequate UV filtering is to make sure to buy a pair of sunglasses that say UV 400. That means they absorb 400nm of UV light and will definitely protect your eye. If you’re not sure about your own pair of sunglasses your optometrist should be able to help you check the lenses to determine if they can help keep your eyes safe!