An eyelash lives for about 5 months. Eyelashes protect the eyes from dust and debris. It is also sensitive to touch, heat and cold, and so serves as a messenger to stimuli.

An eyelash lives for about 5 months. Eyelashes protect the eyes from dust and debris. It is also sensitive to touch, heat and cold, and so serves as a messenger to stimuli.
There are over 100 million light-sensitive cells in the retina. The retina is the light-sensitive region of the eye.