 Typical sunglasses lenses are tinted for protection against bright light or polarized to remove glare; Photochromatic glasses are clear in dark or indoor conditions, but turn into sunglasses when in they come in contact with ultraviolet light.Most over the counter sunglasses do not have corrective power in the lenses; however, special prescription sunglasses can be made.Specialized glasses may be used for viewing specific visual information, for example 3D glasses for 3D films (stereoscopy).