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
Eye bank diseases such as HIV, hepatitis B, hepatitis C, human cytomegalovirus, syphilis, and sometimes others. The blood type is also tested, although corneas do not receive any blood supply and match typing is not necessary for transplantation. If the entire eye is enucleated during the original recovery, then the cornea and part of the sclera are removed and placed in a container with preservation medium, and the sclera is cleaned and then preserved in alcohol. The corneas are visually examined and evaluated underneath a slit-lamp, and the number of endothelial cells are counted underneath a specular microscope. The Eye Bank Association