A blink of an eye is an extremely rapid movement, but it is not typically measured in terms of speed or velocity. The speed of a blink is not commonly expressed in miles per hour (MPH) because it is a measure of the time it takes to close and reopen the eyelids.
On average, a blink of an eye lasts for about 300 to 400 milliseconds (0.3 to 0.4 seconds). To convert this to a measure of speed, we would need additional information, such as the distance traveled by the eyelid during a blink. However, since the distance is minimal and the purpose of a blink is to lubricate and protect the eye, measuring its speed in MPH would not provide a meaningful or practical value.