Photoreceptors-blindness

== = = = = =__What is blindness?__=
 * Blindness is the condition on not having or lacking visual perception because physiological or neurological problems
 * People who have some sight (able to see small amounts of light and shadows) are sometimes called “legally blind”
 * A person is considered blind when their vision is 20/200 or worse in the better eye

__How does seeing happen?__

 * The brain and the eyes work together along with other different parts of the eyes
 * Together they are able to focus on light and images


 * The special nerves in the eyes send what we need to see to the brain and the brain processes and we are able to see

__What causes blindness?__

 * Sometimes when the person is first born the parts of the eye don’t form correctly
 * The optic nerve sends the picture to the brain and if the brain has trouble processing the information the person will not be able to see
 * Can also be genetic and passed down
 * Injuries to the occipital lobe of the brain
 * Accidents can also cause blindness
 * Chemical burns
 * Injuries
 * Fishing hooks
 * Fireworks
 * Racket balls
 * Other similar objects
 * Some of the leading causes of blindness include
 * Cataracts
 * Leprosy
 * Vitamin A deficiency
 * Blocked blood vessels
 * Stroke
 * Lead poisoning
 * Age

__Cure for Blindness__

 * Surgery (to get rid of cataracts)
 * Glasses
 * Certain antibiotics can stop the sight from getting worse
 * There is no cure for people who are completely blind

media type="youtube" key="qvfHY-I_Ywk&rel=1" height="355" width="425"

media type="youtube" key="t0HcJ0kqq-w&rel=1" height="355" width="425" __Sources__ http://en.wikipedia.org/wiki/Blindness http://www.kidshealth.org/kid/health_problems/sight/visual_impaired.html http://www.healthscout.com/ency/1/003040.html