 In this video, we will demonstrate how to use a tonal pin to measure intraocular pressure. Before measurement, we need to numb the patient's cornea as it contains the highest concentration of nerve endings anywhere in the body. This is why getting something in your eye can be so irritating. A nice way to administer the numbing medicine is to ask the patient to look upwards and then drop the medicine into the lower eyelid. So we'll take one of these films, we're gonna use one each time, keep it sterile, and we'll turn on the device pressing this once, now it's ready to go. To use the tonal pin, gently tap or aplinate the tonal pin tip to the cornea, using care to tap perpendicularly. Coming from an oblique angle or sliding the tip across the cornea will cause inaccurate and inconsistent measures. So here the tonal pin, click or chirp about 10 times and then it will display the IOP as well as the confidence interval.