The sun has the ability to damage more than just a person's skin. Studies have shown that the sun's UVA and UVB rays can also cause damage to different parts of the eye and affect vision over time. Both UVA and UVB are beyond the visible spectrum, which means that they can't be seen with the naked eye. UVA is made up of longer wavelengths, and some experts disagree as to whether these light rays are damaging to the eyes. UVB light, however, is the most damaging and the main reason why people need to protect their eyes and skin while outdoors. Since results are inconclusive, it is safest to protect one's eyes against both UVA and UVB radiation.