Eyes

Fastest Reacting Muscle

• The eyes have the fastest-reacting muscles in the whole�body. It�contracts in 1/100th of a second (1^✔ ✔Trusted Source
  Strabismus and eye muscle function
  
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• The eyes contain more than 50% of the sensory receptors in the human body (2^✔ ✔Trusted Source
  Anatomy, Head and Neck, Eye
  
  Go to source).

Cornea

• The cornea is clear and covers the colored iris and pupil.
• The cornea is the only part of the human body that doesn�t contain blood vessels (3^✔ ✔Trusted Source
  Absence of blood and lymphatic vessels in the developing human cornea
  
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Eye Blinking

• The average adult blinks 12 times per minute.
• When we blink, we close our eyes for 0.3 seconds (4^✔ ✔Trusted Source
  High-speed camera characterization of voluntary eye blinking kinematics
  
  Go to source).

Size of the Eyeball

• The diameter of an adult eyeball is around 2.5 cm.
• The human eyeball is 24.5 mm long (5^✔ ✔Trusted Source
  Variations in Eyeball Diameters of the Healthy Adults
  
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Eyelashes

• Eyelashes grow at a rate of 0.12 to 0.14 mm per day.
• There are about 90 to 160 lashes on the upper eyelid and 75 to 80 lashes on the lower eyelid.
• It takes about eight weeks for lashes to grow back after being pulled out (6^✔ ✔Trusted Source
  Anatomy, Head and Neck: Eyelash
  
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Lens

• The lens of the human eye is composed of 66% water�and 33% protein (7^✔ ✔Trusted Source
  Lens Protein
  
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Color Blindness

• Color blind people find it hard to distinguish colors like green�and red (8^✔ ✔Trusted Source
  Types of Color Vision Deficiency
  
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• At birth, everyone is color blind (9^✔ ✔Trusted Source
  Infant color perception: Insight into perceptual development
  
  Go to source).

Eye Color

• Iris determines the color of the eye.
• Brown is the most common eye color in the world (10^✔ ✔Trusted Source
  Molecular and biochemical mechanisms of human iris color: A comprehensive review
  
  Go to source).

Retina

• The retina plays a vital role in vision by capturing the light that enters your eye and translating it into the images you see (11^✔ ✔Trusted Source
  Anatomy, Head and Neck: Eye Retina
  
  Go to source).

Rods and Cones in the Retina

• Retinas consist of light-sensitive cells called rods and cones.�Rods�register�the shapes of images and respond to low�levels of light while�cones respond to bright light and�register the color of images (12^✔ ✔Trusted Source
  Molecular bases of rod and cone differences
  
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• The retina has about 6 million cones and over 100 million rods.

Tears

• Newborns will cry out without tears for the first three to six�weeks (13^✔ ✔Trusted Source
  How Tears Work
  
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• Tears help protect our eyes from infection and irritation (14^✔ ✔Trusted Source
  Older adults have less tear production. Aging: A Predisposition to Dry Eyes
  
  Go to source).