Coloured Filters help to enhance contrast and reduce dazzling.  They are available in a frame to be worn over a standard pair of spectacles or as a clip-on filter attached to the top of a spectacle frame which can be flipped up or down as required e.g. when going inside.  Especially suitable for outdoor use, they help to filter out harmful ultra violet light.  Different colour tints are available to improve the vision with particular eye conditions. 

Each filter colour outlines uses that the filters are particularly recommended for but selection can also be made on cosmetic colour choice together with the amount of light transmission needed for the tasks to be undertaken whilst wearing them.