
- Organ Name: Eye
- Organ System: Visual System (sensory nervous system)
- Organ Purpose: Sight
- Organ Count: 2, left eye and right eye
- Organ FMA ID: 54448
- Organ TA ID: A15.2.00.001 and A01.1.00.007
23 Eye Facts for Kids
- The eyes are an organ that allows humans to have vision and see things.
- Humans have two eyes, the left eye and the right eye.
- The human eye has around two million working parts to help you see.
- Eyes are part of the sensory nervous system, which is part of the human nervous system.
- The human eye can tell the difference between about 10 million colors.
- The average height of an adult human eye is 0.93”.
- The average width of an adult human eye is 0.95”.
- The average depth of an adult human eye is between 0.86 and 0.97”.
- The average human eye weighs less than an ounce (0.98 oz.).
- The human eyeball reaches it full size by the age of 12 years old.
- There are three layers or coasts that make up the human eye and they are the outer layer (fibrous tunic), the middle layer (vascular tunic) and the innermost layer (retina).
- The outer layer of the eye (fibrous tunic) contains the cornea and the sclera.
- The middle layer of the eye (vascular tunic) contains the choroid, ciliary body, iris and the pigmented epithelium.
- The innermost layer of the eye contains the retina and blood vessels.
- The human eyes blink between 15 and 20 times a minute. That means you blink up to 1,200 times per day and over 10.5 million times a year.
- Someone who is shortsighted has an eyeball that is larger than normal and is unable to see things clearly far away.
- Someone who is farsighted has an eyeball that is shorter than average and is unable to see things clearly close-up.
- The human eyes can be one of sixteen different colors according to the Martin scale.
- The Martin scale has eye colors from light blue to dark brown-black.
- The most common eye color worldwide is brown.
- A human can have two different color eyes, and this is called heterochromia iridum or heterochromia iridis.
- The Foundational Model of Anatomy ID for the eye is 54448
- The Terminologia Anatomica IDs for the eyes are A15.2.00.001 and A01.1.00.007.
Pictures of the Human Eyes

A diagram of the different parts of the human eye.Credit: Unknown

A picture of four different colors of the human eye.Credit: LittleThings

A side view picture of a brown colored human eye.Credit: Patrick Brinksma / Unsplash
Additional Resources on the Human Eyes
- How the Human Eye Works – Basic information on the human eyes work on the National Keratoconus Foundation website.
- Eye Disorders – Learn about the different disorders that can affect the human eyes on the CDC website.
- Human Eye – Britannica – Read more about the human eye on the Britannica website.
- Human Eye – Wikipedia – Discover more cool eye facts on the Wikipedia website.