The invisible contact lenses to see invisible marked cards is different to the normal cntact lenses, yet you can't see any differneces. The contact lenses have small purplish filters built into the lens. When you put the contact lenses in your eyes and you are able to read luminous markings. The markings can be applied to the back of poker playing cards.
The contact lenses can usually read all the color marked cards, including the red, the blue, the gold, the black, the green and so on. The contact lenses are the most effective and discreet way to read the invisible markings.
The contact lenses are made of the same material regular contact lenses are made out of. The size of the entire contact lens is 13 mm which is the standard size of contacts.