Silmänräpäytys

Silmänräpäytys, known in English as blinking, is a rapid, involuntary closing and opening of the eyelid. It is a reflex action that serves several crucial functions for the eye. The primary purpose of blinking is to moisten the surface of the eye, the cornea, by spreading a thin layer of tears. This tear film lubricates the eye, washes away small particles of dust and debris, and contains antibacterial agents that help prevent infection. Blinking also helps to clear the vision by removing any foreign matter that may have settled on the eye's surface.

The blink reflex can be triggered by various stimuli. The most common is simply the sensation of dryness or irritation on the eye's surface. Bright lights can also induce blinking, as can a sudden approach of an object towards the eye, a protective reflex to prevent injury. Some sounds or even changes in breathing patterns can also trigger a blink.

The frequency of blinking varies depending on factors such as environmental conditions, fatigue, and individual habits. For example, people tend to blink less often when concentrating intensely on a task, such as reading or using a computer screen. Conversely, in dry or windy conditions, the blink rate may increase to compensate for increased tear evaporation. While primarily an involuntary action, conscious control over blinking is also possible.