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How can we use lenses to correct vision?

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Presentation on theme: "How can we use lenses to correct vision?"— Presentation transcript:

1 How can we use lenses to correct vision?

2 How can we use lenses to correct vision?
If the image is turned upside down too soon, what lens would we use? What if the image was turned upside down too late? What lens would we use?

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4 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

5 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

6 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

7 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

8 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

9 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

10 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

11 c. Farsightedness- image formed
behind retina a. Normal eye b. Nearsightedness-image formed in front of retina Corrected with concave lens Corrected with convex lens No correction needed Eyeball too long Eyeball too short

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13 Iris: color of eye

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15 Iris: color of eye Lens: double convex

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17 Iris: color of eye Lens: double convex Cornea: single convex

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19 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in

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21 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in Ciliary Muscle: opens up pupil in dim light, closes in bright light

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23 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in Ciliary Muscle: opens up pupil in dim light, closes in bright light Vitreous humour: transparent jelly of salts and protein

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25 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in Ciliary Muscle: opens up pupil in dim light, closes in bright light Vitreous humour: transparent jelly of salts and protein aqueous humour: is a thick watery substance filling the space between the lens and the cornea.

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27 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in Ciliary Muscle: opens up pupil in dim light, closes in bright light Vitreous humour: transparent jelly of salts and protein aqueous humour: is a thick watery substance filling the space between the lens and the cornea. Sclera: white covering

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29 Iris: color of eye Lens: double convex Cornea: single convex Pupil: opening that lets light in Ciliary Muscle: opens up pupil in dim light, closes in bright light Vitreous humour: transparent jelly of salts and protein aqueous humour: is a thick watery substance filling the space between the lens and the cornea. Sclera: white covering Optic nerve: sends picture to the brain

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31 Retina: the picture is upside down here

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33 Retina: the picture is upside down here
Made up of millions of tiny, light-sensitive cells called rods and cones

34 Retina: the picture is upside down here
Made up of millions of tiny, light-sensitive cells called rods and cones Rods: distinguish among black, white and gray; allows you to see in dim light

35 Retina: the picture is upside down here
Made up of millions of tiny, light-sensitive cells called rods and cones Rods: distinguish among black, white and gray; allows you to see in dim light Cones: respond to color, 3 types: red, green and blue. Only function in bright light

36 Colorblind? The normal human retina contains two kinds of light sensitive cells: the rod cells (active only in low light) and the cone cells (active in normal daylight and responsible for color perception). Normally, there are three kinds of cones (each one sensitive to a specific range of wavelengths): "red" cones (64%) "green" cones (32%) "blue" cones (2%) The different kinds of inherited color blindness result from partial or complete loss of function of one or more of the different cone systems.

37 Different Types of Color Blindness
Monochromacy: occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension. Total color blindness-see everything as white, black and shades of gray Dichromacy: occurs when only one of the cone pigments is missing and color is reduced to two dimensions. Partial color blindness red-green blue-yellow


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