Detection of eyes/face via webcam

A good description of what we would like to achieve is in this video [login to view URL] We would like a web application (ideally in Flash) that we can use on our website to detect user´s eyes via their webcam. It should also be able to measure in real time the actual distance between the eyes, using some scale object. We thought of using a credit card that can be detected and it has a universal standard size, but any suggestions from you on how to measure scale are welcome.