Light from the sun contains a spectrum of wavelengths. We can see some wavelengths – the visible spectrum but we cannot see wavelengths such as infra-red and ultraviolet (UV) light. There is good evidence that too much UV light can damage the eyes. In particular, a small area of the retina called the macula can be damaged which affects the ability to read and see small detail. Excessive exposure to UV light can also cause the lens in the eye to go hazy – cataracts. Photochromic lenses automatically adjust according to the brightness of the light changing from almost clear to a full sunglass tint in the sun. This provides comfortable vision under all conditions and excellent protection from UV.