Why do our eyes blink?

Answer: To spread tears and protect eyes

To exercise eye muscles — Wrong. While eye muscles do move during blinking, this isn't the purpose. Blinking spreads tear film across the cornea to keep eyes moist and flush away debris.

To spread tears and protect eyes ✓ — Correct! Blinking is important for eye health. Each blink spreads a thin tear film across your cornea, keeping it moist and washing away dust and debris. This tear layer has three parts: mucus, water, and oil. You blink about 15-20 times per minute automatically. The reflex is controlled by the trigeminal nerve and protects against dryness and infection.

To block bright light — Wrong. Squinting blocks bright light, not blinking. Blinking's main function is to spread tears across the eye surface for moisture and protection, controlled by the trigeminal nerve.