Optical lens coatings provide a sharper and more contastful image by reducing glare and internal light loss, eliminating reflections and ensuring an even light transmission. There are different levels and qualities of coatings, but almost all modern consumer optics have some type of optical coating. You tend to see either multi-coated, which means at least one of the major optical elements has coatings, or fully coated, where all glass surfaces have a layer of coating.