Contact Lens with Moiré Patterns for High‐Precision Eye Tracking

Abstract Eye tracking is a crucial technology for understanding human attention and cognitive processes, with applications in scientific research, clinical diagnostics, and assistive technologies, playing a central role in augmented and virtual reality devices. Yet, achieving high‐precision measurements remains challenging due to limitations in current approaches. Existing computer vision methods require complex illumination systems and consume significant power, while contact lens‐based solutions rely on bulky electronics or require specialized fabrication. Here, a passive optical contact lens incorporating micrometer‐scale moiré gratings is demonstrated that achieves high angular resolution through parallax‐sensitive pattern analysis. This approach leverages the interference between two slightly mismatched periodic gratings to create macroscopic moiré patterns whose relative shifts encode viewing angle with extraordinary sensitivity. By analyzing multiple moiré patterns simultaneously, an angular precision of 0.28° across a ±15° range is achieved. The system requires only standard imaging hardware without auxiliary illumination, enabling continuous monitoring with minimal power consumption. Experimental validation demonstrates robust performance under realistic conditions, with the passive nature of the lens eliminating biocompatibility and power supply challenges. This parallax‐based sensing principle opens new possibilities for minimally invasive, high‐precision tracking in augmented reality systems and medical diagnostics, potentially transforming applications ranging from next‐generation displays to neurological assessment tools.