wangemann vision 1

Question 1

what is the mammilian chromophore?

Answer 1

retinal

Question 2

what is the dual nature of light?

Answer 2

1. wave

2. photon

Question 3

convex lens focal point

Answer 3

positive focal distance

Question 4

concave lens focal point

Answer 4

negative focal distance

Question 5

focal power is measured in what?

Answer 5

diopter

Question 6

diopter =?

Answer 6

1 / focal distance (m)

Question 7

what determines focal power?

Answer 7

1. shape of lens
2. refractive index of lens material and surrounding medium
3. wavelength

Question 8

what are the additive colors?

Answer 8

RGB, addition to white

Question 9

what are the subtractive colors?

Answer 9

CMYK, subtract to black

Question 10

what is the fovea centralis?

Answer 10

pit-like structure in the central viewing area that has the highest concentration of photoreceptor cells
-humans, monkeys and some birds

Question 11

what is the area centralis?

Answer 11

flat area in the central viewing area with a higher concentration of photoreceptor cells
- dogs, cats, most animals

Question 12

what is the macula lutea?

Answer 12

central area of the human retina, where photoreceptors store yellow pigments

Question 13

what light does yellow pigment absorb

Answer 13

blue

Question 14

in the anableps underwater vision, what provides the main refraction?

Answer 14

lens

Question 15

in the anableps above water vision, what provides the main refraction?

Answer 15

cornea

Question 16

what is emmetropria?

Answer 16

a status of normal vision where a relaxed ciliary muscle flattens the lens to project a focused image of far objects onto the retina

Question 17

is there accommodation in emmetropia?

Answer 17

no

Question 18

accommodation occurs when looking near or far?

Answer 18

near

Question 19

what happens to the ciliary muscle, zonular fibers and lens in accommodation?

Answer 19

ciliary muscle contracted
zonular fibers relaxed
lens is rounded

Question 20

presbyopia is what

Answer 20

• aging - stiff lens
• reduced accommodation
• corrective lens = convex

Question 21

hyperopia is what

Answer 21

• far-sighted
• bulbus too short
• corrective lens = convex

Question 22

myopia is what

Answer 22

• near-sighted
• bulbus too long
• corrective lens = concave

Question 23

astigmatism

Answer 23

oval lense

Question 24

maintenance of corneal transparency depends on what ?

Answer 24

active ion transport

Question 25

can corneal epithelium regenerate?

Answer 25

yes (5-7 days)

Question 26

can corneal endothelial cells regenerate?

Answer 26

no

Question 27

what is reshaped by a laser in LASIK surgery?

Answer 27

corneal stroma

Question 28

do cells of the lens have organelles?

Answer 28

no

Question 29

what is the largest avascular organ of the body?

Answer 29

the lens

Question 30

what is transparency of the lens dependent on?

Answer 30

1. ion transport | 2. delivery of nutrients and antioxidants to fiber cells

Question 31

the lens circulatory system is driven by what ion?

Answer 31

Na+

Question 32

how can cataracts be corrected?

Answer 32

removal of crystalline lens and implanting yellow artificial lens

Question 33

what cells secrete the aqueous humor?

Answer 33

ciliary epithelium

Question 34

normal pressure in the eye

Answer 34

15 mmHg

Question 35

glaucoma causes what?

Answer 35

retinal damage due to elevated intraocular pressure

Question 36

what commonly causes glaucoma?

Answer 36

blockage of the efflux pathway

Question 37

open angle glaucoma is

Answer 37

cellular debris

Question 38

closed angle glaucoma is

Answer 38

the lens has moved forward | -medical emergency

Question 39

is all retinal pigmented epithelium (RPE) pigmented?

Answer 39

no

Question 40

RPE digests what?

Answer 40

photoreceptor outer segments

Question 41

nocturnal animal eyes

Answer 41

1. big eye/pupils 2. high density of rods 3. tapetum lucidum

Question 42

what is the function of the tapetum lucidum?

Answer 42

reflects photons back into the retina

Question 43

what makes up the tapetum lucidum?

Answer 43

1. tapetum cellulosum (dogs, cats ferrets, etc) | 2. tapetum fibrosum (horses, cows, sheep, etc)

Question 44

tapetum cellulosum

Answer 44

reflective material consists of cells that store densely packed zinc-cysteine

Question 45

tapetum fibrosum

Answer 45

reflective material that consists of extracellular densely packed collagen fibers

Question 46

posterior vitreous detachment

Answer 46

with age, the vitreous body liquefies and detaches from the retina (floaters)