Everyone should wear some kind of eye protection from the sun. This is true for all people of all age groups, and for any time of the year, even on cloudy days. Too much exposure of the eyes to the sun's rays can result in severe damage, for example cataracts, vision loss, or even cancer. So it is important to not only wear sunglasses, but to choose the proper kind.
Luckily, most sunglass manufacturers display the protection the sunglasses offer from the sun. They do this by illustrating the "UV Protection" percentage, and perhaps "UVA" and "UVB" on their labels. UV stands for Ultraviolet Radiation, and UVA and UVB are different wavelengths of UV.
UV causes skin aging and cataracts, so sunglasses must offer complete protection from it. The best sunglasses offer 99 to 100% protection from harmful UV rays, and so it is prudent to look for sunglasses that offer this degree of safety.
Also important is to get sunglasses that will guard against the sun