UV & Eyes

100% UV protective sunglass lenses are essential to prevent damage to the eye from the sun's harmful UV (ultraviolet) radiation.

The reason UV is so dangerous is because, unlike the sun's infrared and visible rays which manifest themselves as heat and light, it is not easy to detect. Excessive exposure to UV light can cause permanent damage to the eyes' surface or internal structures resulting in corneal opacity or cataract.

Lenses that absorb UV don't necessarily need to be dark although most are and a 100% UV absorbing filter can be included in spectacles with only a slight cosmetic tint. Alternatively light-sensitive (photochromic) lenses, which change with the light, can also offer full UV protection even when they are in their lighter mode.

For your own protection, however, only ever wear 'off the shelf' sunglasses that display the appropriate CE mark and guarantee to absorb all UV light up to 400nm.

WARNING:

Sunglasses without UV protective lenses are potentially dangerous and should be avoided.

This is because the iris in your eye reacts to visible light, causing the pupil to become smaller in bright conditions. However, when light is restricted, for example by tinted lenses, the pupil opens wider to let in more light. If the tinted lenses are not 100% UV protective your eye will, in fact, absorb more UV than if you had not worn sunglasses at all!

It is especially important to remember this when you are next faced with the temptation of buying 50p toy sunglass for your children at the seaside!