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 Tandyla The Eye of Tandyla "The Eye of Tandyla" is a fantasy story by American writer L. Sprague de Camp, part of his Pusadian series. It was first published in the magazine "Fantastic Adventures" for May, 1951, and first appeared in book form in de Camp's collection "The Tritonian Ring and Other Pusadian Tales" (Twayne, 1953). The story has also appeared in the magazine "Fantastic" for November 1965, the anthologies "Time Untamed" (1967), "The Magic of Atlantis" (1970), "Wizards" (1983), and "The Mammoth Book of Seriously Comic Fantasy" (1999) (also published as "The Mammoth Book of Comic Fantasy II"), and the