Measuring pupil dilation changes in real-time through users webcam

I need to be able to continuously measure pupil area and/or diameter online. Ideally, I would like a variation of the below project. [login to view URL] This link is to a project that uses the users webcam to detect eye gaze. I want it similar to the aforementioned project but rather than track eye gaze, I want the project to detect the pupils and measure them such that we can record measurements every second (or less). We should be able to easily output data from the measurements as well. Alternatively, a MATLAB script that can accurately record and measure pupil diameter changes from videos.