Chapter 3

Question 1

The fovea contains mostly…?

Answer 1

Cones

Question 2

The peripheral retina contains mostly…?

Answer 2

Rods

Question 3

What is more sensitive to dim light?

Answer 3

Rods

Question 4

What do on and off center receptive fields detect?

Answer 4

Edges and Contrast

Question 5

Dark Adaptation makes it…?

Answer 5

harder to see color in low light

Question 6

Accommodation

Answer 6

-Allows the eye to change focus between near and far objects
-Ciliary muscles get tighter

Question 7

What do we use for edge detection

Answer 7

Receptive Fields

Question 8

Iris

Answer 8

Muscle that controls light amount

Question 9

Optic Nerve

Answer 9

Carries info from retina to the brain

Question 10

4 Points of Refraction

Answer 10

-Cornea
-Aqueous humor fluid
-Crystalline lens (main refraction pt)
-Vitreous humor fluid (floaters)

Question 11

Myopia (5)

Answer 11

-Nearsighted
-Under fovea
-Diagnosed by 20 and behavioral problems
-Heritable or acquired
-Cornea/lens focusing issue (refractive or axial)

Question 12

Hyperopia (6)

Answer 12

-Farsighted
-Over fovea
-Corneal lens focusing issue (short eye)
-Heritable or acquired
-Diagnosed in childhood or 40+
-Headaches

Question 13

Presbyopia (4)

Answer 13

-Blurry vision when reading, looking up close, or in dim light
-Lens gets tighter
-You need more light, holding objects further away
-Age related 40+

Question 14

Astigmatism (5)

Answer 14

-Blurred or distorted vision
-Uneven cornea curve or lens scattered light
-Any age diagnoses
-Football shape
-Worse at night

Question 15

Macular Degeneration (4)

Answer 15

-Affects central vision (blindspot)
-Age related
-Dry has cell breakdown and slow vision loss
Wet has leaky blood vessels and fast vision loss

Question 16

Retinis Pigmentosa (4)

Answer 16

-Affects peripheral vision
-Tunnel vision
-Genetic and uncommon
-Dark cloud closing in/weird clumps

Question 17

Rod Details (3)

Answer 17

-Large + cylindrical
-Peripheral retina has more rods
-120 million rods

Question 18

Cone Details (3)

Answer 18

-Small and tapered
-Fovea only has cones
-6 million cones

Question 19

Visual Transduction

Answer 19

Retinal absorbs 1 photon

Question 20

Visual pigment molecules

Answer 20

-Opsin (large protein)
-Retinal (light sensitive molecule)

Question 21

Isomerization

Answer 21

Retinal changes shape

Question 22

Blind Spot

Answer 22

Where optic nerve + blood vessels leave the eye

Question 23

Dark Adaptation is achieved by

Answer 23

Increasing photosensitivity

Question 24

Light Adaptation is achieved by

Answer 24

Decreasing photosensitivity

Question 25

Rod Adaptation (2)

Answer 25

-Rod monochromat (RARE) only see black and white -Sensitivity increases for 25 minutes and levels off

Question 26

Cone Adaptation (2)

Answer 26

-Test light only stimulates cones -Sensitivity increases 3 to 4 minutes then levels off

Question 27

Spectral Sensitivity-Rods (2)

Answer 27

-More sensitive to short wavelength light -500nm

Question 28

Spectral Sensitivity-Cones (1)

Answer 28

-Most sensitive at 560nm

Question 29

Spectral Sensitivity

Answer 29

Absorption spectra of visual pigments

Question 30

High Illumination

Answer 30

More inhibition which decreases neural responding

Question 31

Chevreul Illusion

Answer 31

Inhibitory areas surround are lit up by more intense light on the light boarder side

Question 32

Rod Convergence (3)

Answer 32

-Less light to respond -Useful for shapes and motion -More rods in gang cells, inc. response chance

Question 33

Cone convergence (4)

Answer 33

-Small receptive fields 1:1 -Good for color and detail -More light to respond -2 points touching