The human eye pp1

BY: E M I LY H U N D T

THE HUMAN EYE

DIAGRAM OF THE HUMAN EYE

http://63.240.118.132/images/Senior%20Site/Section%201/eye-diagram.jpg

EYE PARTS

Iris• Round, colored part of

the eye ball• Helps control the

amount of light that enters the eye

Lens• Clear structure in the

eye• Focuses light rays to

the retina

http://www.medterms.com/script/main/art.asp?articlekey=4044

EYE PARTS

Pupil• Dark hole of the eye• Controls how much

light goes in the eye

Retina• Nerve layer• Lines back of eye• Creates urges that

travel through the optic nerve to the brain

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EYE PARTS

Cornea• Clear outer layer of

the eye• Focuses light in the

eye

Optic Nerve• The nerve that

connects the eye to the brain• Carries impulses

formed by the retina to the visual cortex of the brain

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WHAT IS NEEDED TO SEE?

• If you guessed light, you are correct.

• The human eye can not see without some sort of light source.

ARE ALL PARTS OF THE EYE IMPORTANT FOR SEEING?

• The answer: Yes. Each part of the eye plays a different role, and each are equally important.• For example: The optic nerve connects to the

brain so you can remember things you see.• The lens focuses the light rays to the retina. • The pupil controls the amount of light that enters

the eye. • All are very important for seeing clearly.

WHAT DOES IT MEAN TO BE BLIND?

• People who are blind can not see.• Some blind people can see only shapes, bright lights, and dull lights. •One is considered blind if their vision is no better than 20/200.

WHAT DOES IT MEANTO BE BLIND

CONTINUED

• Some are born blind• Some become blind• Causes of blindness is if the optic nerve is

not functioning or is damaged.• When the cornea or the lens gets clouded

over, it does not let light in. This also causes blindness.

RODS AND CONES

• Both are parts of the retina• Rods work in dim light

• Cones are used in bright light• Both are used for seeing colors

CONES

• Cones are sensitive to color• They are less sensitive to light• The cones are accountable for high resolution vision.

RODS

•Not sensitive to color• Responsible for dark-adapted vision• Rods are good motion sensor.

WHAT IS 20/20 VISION?

• “Normal vision”• Can see at twenty feet what most people

can see at twenty feet• Does not mean perfect vision, it only

means the clarity of vision at a specific distance.

WORK CITEDPICTURES

• Slide 3-Lens picture-

• Slide 3-Iris picture-

• Slide 4-Pupil picture-

• Slide 4-Retina picture-

• Slide 5-Cornea picture-

• Slide 5-Optic Nerve picture-

http://excelens.in/images/newsletter/newsletter_clip_image003.jpg

http://fc02.deviantart.net/fs27/f/2008/042/0/0/Iris_Eye_Macro_Stock_by_zpyder.jpg

http://www.atlanta2020.com/wp-content/uploads/2011/08/DilatedPupil.jpg

http://www.topnews.in/healthcare/sites/default/files/retina.jpg

http://www.rustoneyeinstitute.com/images_content/cornea.jpg

http://www.daviddarling.info/images/optic_nerve.jpg

WORK CITEDINFORMATION

1. Adler, Irving, and Ruth Adler. Your Eyes. New York: The John Day Company, 1962. Print.

2. "Definition of Iris." MedicineNet.com. MedicineNet, 2011. Web. 10 Oct 2011. <http://www.medterms.com/script/main/art.asp?articlekey=4044>.

3. "Visual Acuity: What is 20/20 Vision?." American Optometric Association . American Optometric Association, 2011. Web. 10 Oct 2011. <http://www.aoa.org/x4695.xml>.

4. http://hyperphysics.phy-astr.gsu.edu/hbase/vision/rodcone.html#c4