SENSE OF SIGHT

- We perceive shapes , distance , movement , color , heat and depth by our sense of sight . The organ for the sense of sight is the eye , about the shape of ping - pong ball . The eye alone cannot make sight possible . It works with the brain and in the outside , needs light to be present .

PEOPLE WHO ARE BLIND

Blindness is the inability to see any thing , this is because they cannot see clearly , but only see unfocused shapes or colors , blindness is mostly caused by malnutrition and diseases of old people .

parts
The eye consist in three layers : The autor layer consist of the sclera and the cornea . The middle layer consist of the choroid , ciliary body and iris . The inner layer consists of the retina .

HOW VISION WORKS

Visual perception begings as soon as the eye focuses light onto the retina, where its absorbed by a layer of photoreceptor cells this cell convert eight into electrochemical signals.
These cells are divided in two types, roads and cones, named for their shape. Red cells are responsible for our night vision, and respond well to dim light.


FUN FACTS
- Dolphins sleep whit one eye open .
- People blink 15 times per minute on overage .
- Human eyes are made of over two millions working parts .
- Newborn babies see everything upside down until the brain learns to process everything right side up .