Part I: Card Game Cheating · Collusion & Electronic Cheating at Card Games

Scam #31: Infrared Marked Cards with Contact Lenses

How it works

Playing cards are marked on the backs with invisible infrared ink that is completely invisible to the naked eye and standard cameras (which have IR-cut filters). The cheater wears special contact lenses or glasses with infrared band-pass filters that make the markings glow clearly, allowing them to read card values without any visible indication of cheating. The lenses use a micro-filter embedded in the pupil area (5-8mm diameter) that appears as a slightly tinted contact lens but is hard to detect in normal conditions. The system emits no electronic signals, making it completely invisible to RF detectors.

Where it appears

Poker, blackjack, baccarat, any card game

On the record

Infrared marked cards have been used in gambling fraud for decades. In 2014, Italian Stefano Ampollini was convicted for using infrared contact lenses with marked cards to cheat a casino out of 80,000 euros. PubMed has published research on detecting invisible ink markings using image processing techniques. The technology continues to evolve, with newer inks calibrated to specific wavelengths (850nm or 940nm) to avoid detection by standard security cameras.

Published as a detection reference for surveillance, compliance and gaming-operations professionals. Thresholds and tuning are set by the property. Nothing here is instruction — the method is described so it can be recognised.