Among all types of sunglasses, the regular type has the longest history even though they are quite ordinary. These uniformly tinted sunglasses can cut down the amount of light reaching the eyes. However, regular sunglasses offer the least protection from UV light. In fact, polarized sunglasses are much more popular than regular ones. Polarized sunglass lenses are tinted in tiny, parallel lines quite specially. Reaching the lenses' surface, the sun rays will bounce off in waves. Compared with regular lenses, polarized lenses can deflect the glare when sunlight hits a surface. In this way polarized sunglasses can offer considerably more protection.
In addition to regular sunglasses and polarized sunglasses, there are also specially-treated types. The differences lie in additional treatments of the lenses. For example, sunglass lenses can be made with anti-reflection coating which applies metal oxides to the front and back of the lenses. In this way, reflected light can be blocked by these additional layers in the lenses. In detail, these lenses can reduce the amount of glare, reflections and halos around the lights. Another type is panchromatic lenses which help in increasing darkness when there is more light hitting them. These lenses can also protect the eyes from the brightest light.