Eyes are prone to UVR (Ultra Violet Radiation) just like skin. Exposure to reflected sunlight from snow, water, ice, sand, or concrete even on grey overcast days can result in sunburn of the tissues comprising the surface of the eye as well as the retina. Repeated exposure of unprotected eyes can lead to the risk of cataracts, cancer of the conjunctiva and skin around the eye and snow blindness (ultra violet keratitis, photokeratitis or niphablepsia). Too much UV (Ultra Violet) exposure could also cause melanomas in the uveal tract (coloured part of the eye including the iris).
Eye Protection Factor - EPF
The EPF (Eye Protection Factor) is a measure of the protection provided by eye wear e.g. sunglasses/goggles.
EPF has a numerical rating of 1-10 which classifies how well a lens blocks UVR e.g. a EPF of 9 or 10 transmits minimal UVR
Buying a new pair of sunglasses
When purchasing a new pair of sunglasses ensure they have the following:
They absorb 95% of UVR (ultra violet radiation)
They are rated EPF 10
They are of a wrap around style to offer maximum protection to the sides of your eyes
The frame fits closely to your face
Look for a CE kite mark and British standard mark or UV 400 label
They block 100% UVA and UVB rays
Poorly fitting sunglasses offer poor protection as the sun can be reflected off the back of the lens straight in to the eye.
The UV (Ultra Violet) chemical in sunglasses is invisible. Thus the colour of the lens is not an indication of the level of protection.
In fact some darker lensed sunglasses may cause pupil dilation and let more light in!
Always use sunglasses in combination with other sun protection measures such as: clothing, shade, a hat and sun cream.