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 Heron context of her development as a writer: "The Eye of the Heron" contains the phrase: "A beginning place". Le Guin reused this phrase in the title of her 1980 novel "The Beginning Place". The Eye of the Heron The Eye of the Heron is a 1978 science fiction novel by American author Ursula K. Le Guin which was first published in the science fiction anthology "Millennial Women". "The Eye of the Heron" is a science fiction novel set on the fictional planet of Victoria in a speculative future, probably sometime in the 22nd century, when the planet has been colonized