1. Bellwork
1. Explain the difference between rods and cones. What happens if someone is missing a certain kind of cone?
Answer: Rods work in the dark and see gray tones, shape and movement. Cones see in color and only work in bright light. If someone is missing a certain kind of cones, they will be colorblind (not able to see that specific color.
SWBAT describe the structure of the eye.
SWBAT explain the pathway of light.
SWBAT differentiate between different types of vision.
Example

2. Special Senses
The Eye and Vision

3. Anatomy of the Eye Lens: focuses light entering eye onto the retina
When we are young, lens is flexible and clear.
As we age it gets hard and opaque causing cataracts
Cataracts can eventually cause blindness, can be treated by surgical implant

4. Anatomy of the Eye Lens divides eye into 2 fluid filled chambers
Anterior segment
Contains aqueous humor (clear, watery)
Posterior segment
Contains vitreous humor (gel-like)
These fluids maintain intraocular pressure, Glaucoma is the result of high pressure. It can cause pain, vision problems, and blindness.

5. Pathway of Light
When light passes through a substance, it is refracted
Refracting power of cornea and humors is constant
Lens changes shape to help focus light
Ciliary body contracts to change lens
More convex = light more bent
Ability to focus on close objects is called accomodation

6. Pathway of Light

7. Correcting Vision Emmetropia: Correct focus Myopia: Nearsightedness
Distant objects are blurry
Focus of light in front of retina
Happens when -
Hyperopia: far sightedness
Near objects are blurry
Focus of light beyond the retina

8. Correcting Vision
Astigmatism – unequal curvatures in different parts of cornea or lens

9. Visual Fields
Binocular vision – “two-eyed” allows for depth perception because our brain fuses a slightly different image from each eye

10. Practice
Label the parts of the eye on your worksheet.
Words to Use:
Aqueous humor
Choroid
Conjunctiva
Cornea
Iris
Lens
Optic disc
Optic nerve
Pupil
Retina
Sclera
Vitreous humor
On the back find the word that doesn’t belong and explain why it doesn’t belong.
Due Tomorrow!
Vocab Due Wednesday!