Visera Link uses advanced facial blood-flow analysis to determine heart rate, heart rate variability, breathing rate, skin age, and mental stress level. This technology is known as Transdermal Optical Imaging, or TOI. Studies show that TOI rivals traditional methods of measuring cardiovascular health, such as electrocardiogram testing. Watch this 3 minute video HEREto understand how the Visera Facial Link Scan works. The unique, real-time measurements from the Link face scan are incorporated into the Visera scanning algorithm, which accurately determines your priority score for each biomarker, product, and service scanned.