Eye

Question 1

what is a blowout fracture?

Answer 1

indirect traumatic injury that displaces orbital walls

Question 2

infraorbital bleeding and increased pressure from orbital fractures causes?

Answer 2

exophthalmos (protrusion of eye)

Question 3

tumors in the orbit cause?

Answer 3

exophthalmos

Question 4

tumors of the middle cranial fossa get into the orbit through?

Answer 4

superior orbital fissure

Question 5

tumors in the temporal or infratemporal fossa get into the orbit through?

Answer 5

inferior orbital fissure

Question 6

why is a lateral approach to surgery used for the orbit?

Answer 6

when pupil is turned medially, 2.5 cm of eye is exposed since lateral wall of orbit doesn’t extend as far anteriorly as does the medial wall

Question 7

lesion of CN III causes?

Answer 7

paralysis of levator palpebrae superioris and thus the superior eye lid droops (ptosis)

Question 8

damage to CN VII causes?

Answer 8

paralysis of orbicularis oculi which prevents eyelids from closing all the way —> no blinking and dry eye occur

Question 9

loss of tonus in the inferior eyelid causes?

Answer 9

lid to fall away from surface of eyeball —> drying of cornea & excessive lacrimation

Question 10

excessive lacrimal fluid can also be caused by?

Answer 10

blockage of lacrimal drainage apparatus

Question 11

if the ducts of the ciliary glands are obstructed?

Answer 11

painful pus producing swelling called a sty (hordeolum) forms on the eyelid

Question 12

cysts of the sebaceous glands of the eyelids are called?

Answer 12

chalazia

Question 13

obstruction of the tarsal gland causes?

Answer 13

inflammation –> tarsal chalazia

Question 14

hyperemia of the conjunctiva is caused by?

Answer 14

irritation from smoke, dust, or chlorine

Question 15

what is conjunctivitis?

Answer 15

inflammation of the conjunctiva “pink eye”

Question 16

how do subconjunctival hemorrhages occur?

Answer 16

trauma, excessively hard nose blowing, coughing, violent sneezing —> rupture of small subconjunctival capillaries

Question 17

the retina and optic nerve develop from?

Answer 17

optic cup

Question 18

what is the optic cup?

Answer 18

outgrowth of embryonic forebrain

Question 19

what does the optic vesicle carry with it as it evaginates from the forebrain?

Answer 19

developing meninges (why CN II is a part of CNS)

Question 20

the pigment layer of retina develops from?

Answer 20

outer layer of optic cup

Question 21

the neural layer of retina develops from?

Answer 21

inner layer of optic cup

Question 22

the layers of the developing retina are separated by?

Answer 22

intraretinal space –> pigment layer becomes fixed to choroid

Question 23

what can cause detachment of the retina?

Answer 23

trauma to eye —> seepage of fluid in between layers of retina

Question 24

the pupillary light reflex tests the integrity of which CNs?

Answer 24

CN II (afferent) and CN III (efferent)

Question 25

why do both pupils constrict when light enters one eye?

Answer 25

each retina sends fibers to the optic tracts of both sides

Question 26

if the parasympathetic pathway to the sphincter pupillae muscle is interrupted?

Answer 26

pupils will dilate because of unopposed sympathetic innervation to the dilator pupillae muscle

Question 27

how can you tell a person has compression of CN III?

Answer 27

ipsilateral slowness of pupillary response to light

Question 28

what is uveitis?

Answer 28

inflammation of the vascular layer of the eyeball (uvea)

Question 29

what is used to view the fundus of the eye?

Answer 29

opthalmoscope

Question 30

edema of the retina is caused by?

Answer 30

increase in CSF pressure ---> slows venous return from retina

Question 31

what is swelling of the optic disc?

Answer 31

papilledema

Question 32

what causes papilledema?

Answer 32

increased intracranial pressure and increased CSF pressure in subarachnoid space around optic nerve

Question 33

what is presbyopia?

Answer 33

changes in the focusing power of the lens caused by aging

Question 34

a loss in transparency of the lens is called?

Answer 34

cataracts

Question 35

how are cataracts fixed?

Answer 35

cataract extraction with intraocular lens implant

Question 36

what is coloboma of the iris?

Answer 36

absence of a section of the iris resulting from the choroid fissure failing to close in the fetus, trauma, or an iridectomy

Question 37

does the iris heal after a coloboma?

Answer 37

no.

Question 38

what causes glaucoma?

Answer 38

blockage of the outflow of aqueous humor through scleral venous sinus into the blood --->increased pressure in anterior and posterior chambers of eye

Question 39

glaucoma can cause what if the retina is compressed and the blockage isn't fixed?

Answer 39

blindness

Question 40

what is hyphema?

Answer 40

hemorrhage within the anterior chamber

Question 41

what happens when the eyeball is enucleated?

Answer 41

removed!

Question 42

after the eyeball is removed, why don't the muscles of the eye retract very far?

Answer 42

their fascial sheaths remain attached to fascial sheaths of eyeball

Question 43

what is the corneal reflex?

Answer 43

touching the cornea with a "wisp" of cotton to initiate a blinking response

Question 44

absence of the corneal reflex suggests?

Answer 44

lesion of CN V1 or CN VII

Question 45

how do you fix a corneal lesion (scarred or opaque corneas)?

Answer 45

corneal transplant

Question 46

what are signs of Horner's syndrome?

Answer 46

constriction of pupil (miosis), ptosis, vasodilation, and absence of sweating (anhydrosis)

Question 47

Horner's syndrome results from?

Answer 47

interruption of cervical sympathetic trunk causing symptoms on ipsilateral side of head

Question 48

what is diplopia?

Answer 48

double vision from loss of function of one or more eye muscles

Question 49

what is occulomotor nerve palsy?

Answer 49

paralysis of SR, MR, IR, levator palpebrae superioris & sphincter pupillae

Question 50

what is abducens nerve palsy?

Answer 50

paralysis of LR

Question 51

obstruction of central artery of retina causes?

Answer 51

instant and total blindness because its an end artery (no anastomosis)

Question 52

blockage of the central vein of the retina is caused by?

Answer 52

thromboplebitis of cavernous sinus

Question 53

occlusion of the central vein of retina results in?

Answer 53

slow and painless loss of vision