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
His Eye Is on the Sparrow His Eye Is on the Sparrow "His Eye Is on the Sparrow" is a Gospel hymn. The song was written in 1905 by lyricist Civilla D. Martin and composer Charles H. Gabriel. It is most associated with actress-singer Ethel Waters who used the title for her autobiography. Mahalia Jackson's recording of the song was honored with the Grammy Hall of Fame Award in 2010. The theme of the song is inspired by the words of David in the Psalms and Jesus in the Gospel of Matthew in the Bible: "I will instruct thee and teach thee in the way which