1. A system for determining closure state of an eye of a subject, said system comprising: a video imaging camera oriented to generate images of an eye of a subject; and a video processor for processing the images generated with the video imaging camera, said video processor detecting an eye in the video images and determining if the images of the eye are noisy, said video processor determining closure state of the eye based on a shape of the eye in the images if the images of the eye are not noisy, and based on changes in the size of the eye over time if the images of the eye are noisy to determine whether the eye is in an open or closed state.