Chapter 13 Eye

Question 1

Name and describe the features of the eye

Answer 1

pupil - opening where light enters eye
Iris - gives color to eyes
sclera - white of eye
cornea - glassy transparent external surface of eye
optic nerve - bundle of axons from retina

Question 2

what is the purpose of the optic nerve

Answer 2

transmission to brain of external images (sight)

Question 3

what is the function of eyelids

Answer 3

protect the eye of foreign particles by means of eyelashes (cilia)
sebaceous glands secrete a lubricating oil onto eyelash

Question 4

describe what conjunctiva is

Answer 4

mucous membrane of eye

lines inside the eyelids to help lubricate the eye with mucus and tears

Question 5

what does the lacrimal apparatus consist of?

Answer 5

superior and inferior lacrimal glands
lacrimal sac
lacrimal ducts
nasolacrimal duct

Question 6

strabismus

Answer 6

eye muscle weakness resulting in eyes looking in different directions at same time

Question 7

esotropia (ST)

Answer 7

eso- = inward
-tropia = turned condition

type of strabismus with inward turning of eye
“cross-eyed”

Question 8

exotropia (XT)

Answer 8

exo- = outward
-tropia = turned condition

type of strabismus with outward turning of eye
“wall-eyed”

Question 9

what is the function of the cornea?

Answer 9

admit and refract light

Question 10

what is the function of the iris and pupil?

Answer 10

smooth muscle that changes size of pupil to control amount of light entering the eye

Question 11

what is the function of the lens?

Answer 11

focus light rays onto retina

Question 12

what are the three layers of the eye?

Answer 12

retina
choroid
sclera

Question 13

what is the function of the retina?

Answer 13

contains sensory receptors

Question 14

what is the function of the choroid layer

Answer 14

supplies blood to eye structures

Question 15

what is the function of the sclera?

Answer 15

tough protective layer of eye

Question 16

what layer is the cornea a part of?

Answer 16

sclera

Question 17

what is aqueous humor and where is it found?

Answer 17

watery fluid

found between cornea and lens

Question 18

what is vitreous humor and where is it found?

Answer 18

semi-solid gel

found between lens and retina

Question 19

explain what refraction is?

Answer 19

bending of a wave when it enters a medium where its speed is different
ex. light is refracted when it passes from a fast medium (air) to a slow medium (water)

Question 20

what is the structure on the eye that causes refraction? what does this mean

Answer 20

cornea and aqueous humor
refracts light rays due to slowing of light at the air-cornea interface

immersing cornea under water will eliminate its refractive power because light travels at the same speed through water and aqueous humor

Question 21

what is the function of the ciliary body?

Answer 21

attaches to lens; pulls on edge of lens which changes shape of lens in order to focus light onto retina

Question 22

define accommodation

Answer 22

changes the shape of the lens to alter the focal distance of the eye;
the change in lens shape is controlled by ciliary body muscles

Question 23

describe briefly the travel path of light rays though the eye

Answer 23

cornea
aqueous humor
pupil
lens
vitreous humor
retina

Question 24

what are photoreceptors?

Answer 24

sensory receptor cells that detect light rays

Question 25

where can you find photoreceptors?

Answer 25

within the retina (inner layer of eye)

Question 26

what kind of color do cones pick up on? when is are they actively used?

Answer 26

color vision | active only in bright light

Question 27

what kind of color do rods pick up on? when are they actively used?

Answer 27

gray tones | active in dim light

Question 28

what is another name for macula lutea? what is it's function and where is it found?

Answer 28

fovea centralis part of retina responsible for sharp, detailed central vision; contains high concentration of cones found center most posterior portion of eye

Question 29

because of refraction, what happens to an image when the optic nerve takes in the information? what corrects this?

Answer 29

image forms upside down | brain take this information and turns it right side up

Question 30

Emmetropia

Answer 30

``` emmetr/o = correct, proper -opia = vision condition ``` state of normal vision

Question 31

what is the location where the optic nerve leaves the eyeball?

Answer 31

optic disk

Question 32

what else leaves through the optic disk besides the optic nerve?

Answer 32

retinal blood vessels

Question 33

there are no rods or cones found at the optic disk, what does this cause within our vision?

Answer 33

blind spot

Question 34

ophthalmologist

Answer 34

ophthalm/o = eye doctor who specialized in treatment of eye

Question 35

optician

Answer 35

``` opt/o = vision -ician = specialist ``` person trained in grinding and fitting corrective lenses

Question 36

optometry

Answer 36

``` opt/o = vision -metry = process of measuring ``` medical profession specializing in examining and testing the eyes and prescribing corrective lenses

Question 37

optometrist

Answer 37

``` opt/o = vision -metrist = specialist in measuring ``` doctor of optometry

Question 38

blepharoptosis

Answer 38

``` blephar/o = eyelid -ptosis = drooping ``` drooping eyelid

Question 39

iridoplegia

Answer 39

``` irid/o = iris -plegia = paralysis ``` paralysis of the iris

Question 40

ophthalmalgia

Answer 40

``` ophthalm/o = eye -algia = pain ``` eye pain

Question 41

ophthalmoplegia

Answer 41

``` ophthalm/o = eye -plegia = paralysis ``` paralysis of one or more of the extraocular eye muscles

Question 42

ophthalmorrhagia

Answer 42

``` ophthalm/o = eye -rrhagia = abnormal flow condition ``` bleeding from eye

Question 43

xerophthalmia

Answer 43

``` xer/o = dry ophthalm/o = eye -ia = condition ``` dry eyes

Question 44

scleromalacia

Answer 44

``` scler/o = sclera -malacia = abnormal softening ``` softening of the sclera

Question 45

photophobia

Answer 45

``` phot/o = light -phobia = fear ``` strong sensitivity to bright light

Question 46

papilledema

Answer 46

``` papill/o = optic disk -edema = swelling ``` swelling of the optic disk

Question 47

myopia

Answer 47

``` myo- = to shut -opia = vision condition ``` nearsightedness; distant objects not seen clearly

Question 48

what can cause myopia?

Answer 48

eyeball being too long; | causes parallel light rays to converge before retina

Question 49

hyperopia

Answer 49

``` hyper- = excessive -opia = vision condition ``` farsightedness; eye cannot see near points

Question 50

what can cause hyperopia?

Answer 50

eyeball being too short; | causes light to be focused behind retina

Question 51

presbyopia

Answer 51

``` presby/o = old age -opia = vision condition ``` visual loss due to old age decreased ability to focus on near objects

Question 52

astigmatism

Answer 52

``` a- = without stigmat/o = point -ism = state of ``` uneven cornea causing blurred vision light rays do not focus sharply on retina

Question 53

corneal abrasion

Answer 53

scraping injury to cornea

Question 54

achromatopsia

Answer 54

``` a- = without chromat/o = color -opsia = vision condition ``` color blindness: unable to perceive one or more colors

Question 55

monochromatism

Answer 55

``` mono- = one chromat/o = color -ism = state of ``` unable to perceive one specific color

Question 56

cataract

Answer 56

damage to lens causing it to become cloudy

Question 57

glaucoma

Answer 57

``` glauc/o = gray -oma = mass ``` increased pressure in fluid of eye which interferes with optic nerve function

Question 58

explain how vision deteriorates with glaucoma

Answer 58

peripheral vision is reduced then tunnel vision develops blindness can ultimately develop

Question 59

what is the commonness of glaucoma?

Answer 59

20% of adults over age 40 | accounts for 15% blindness in America

Question 60

what qualifies as someone being legally blind

Answer 60

having severely impaired vision; | 20/200 acuity (can only see the first row letter E)

Question 61

macular degeneration

Answer 61

``` macul/o = macula lutea -ar = pertaining to ``` deterioration of macula lutea areas of retina causes central vision loss

Question 62

pterygium

Answer 62

hypertrophied conjunctival tissue in inner corner of eye

Question 63

conjunctivitis

Answer 63

``` conjunctiv/o = conjunctiva -itis = inflammation ``` inflammation of the conjunctiva; usually from bacterial infection; "pink eye"

Question 64

hordeolum

Answer 64

purulent (pus) infection of sebaceous gland of eyelid; "stye"

Question 65

ambly/o

Answer 65

dull, dim

Question 66

aque/o

Answer 66

water

Question 67

blast/o

Answer 67

immature, embryonic

Question 68

blephar/o

Answer 68

eyelid

Question 69

cycl/o

Answer 69

ciliary muscle

Question 70

emmetr/o

Answer 70

correct, proper

Question 71

glauc/o

Answer 71

gray

Question 72

macul/o

Answer 72

macula lutea

Question 73

mi/o

Answer 73

lessening

Question 74

mydr/i

Answer 74

widening

Question 75

nyctal/o

Answer 75

night

Question 76

presby/o

Answer 76

old age

Question 77

stigmat/o

Answer 77

point

Question 78

uve/o

Answer 78

choroid

Question 79

vitre/o

Answer 79

glassy