Eye tracking white sclera (limbus tracking). It presents another challenge for vertical eye movements due to obstruction of eyelids. Eye-tracking setups vary greatly: some are head-mounted, some require the head to be stable (for example, with a chin rest), and some function remotely and automatically track the head during motion. Most use a sampling rate of at least 30 Hz. Although 50/60 Hz is more common, today many video-based eye trackers run at 240, 350 or even 1000/1250 Hz, speeds needed in order to capture fixational eye movements or correctly measure saccade dynamics. Eye movements are typically divided into fixations and saccades
The Eye of the World their hands, and is sentenced to death. Moiraine, Lan, and Nynaeve rescue Egwene and Perrin, and all are reunited with Rand and Mat. Thereafter Moiraine determines that Mat must travel to Tar Valon, the Aes Sedai's center of power, to overcome the influence of Shadar Logoth. Loial warns Moiraine of a threat to the Eye of the World, a pool of Saidin untouched by the Dark One's influence, which is confirmed by vivid and disturbing dreams Mat, Rand, and Perrin have had. The Eye of the World is protected by Someshta (the Green Man) and contains one of the seven