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 seals on the Dark One's prison, the Dragon banner of Lews Therin Telamon, and the Horn of Valere. At the civilized world's border, the group enters the Blight (the polluted region under the Dark One's control) to protect the Eye. After a pursuit they meet the Green Man and he reveals the Eye. The group is then confronted by the Forsaken Aginor and Balthamel. As battle ensues, Balthamel and the Green Man slay each other. Soon after, Rand defeats Aginor and uses the Eye to decimate the Trolloc army and defeat Ba'alzamon. As a result, Moiraine concludes that Rand is