SINGLE VISION LENSES
Single vision lenses are for correction for one field of vision. Either for distance, intermediate (computer), or near vision (reading).
PROGRESSIVE LENSES
Instead of having just two or three lens powers like bifocals or trifocals, progressive lenses are true "multifocal" lenses that provide a seamless progression of many lens powers for all viewing distances. With progressive lenses, you can look up to see clearly across the room and in the distance.
TRANSITION LENSES
Photochromic lenses are eyeglass lenses that darken automatically when exposed to sunlight, then fade back when you return indoors. In most cases, photochromic lenses are clear (or nearly clear) indoors and darken to a medium sun tint outdoors. But there are exceptions.
