Orbital Region, Orbit, and Eyeball

Question 1

where do orbital fractures usually occur?

Answer 1

at the 3 sutures b/w the bones forming the orbital margin

Question 2

what is a blowout fracture?

Answer 2

displacement of orbital walls from indirect trauma

Question 3

what fractures may involve the ethmoidal and sphenoidal sinuses?

Answer 3

fractures of medial wall

Question 4

what fractures may involve the maxillary sinus?

Answer 4

fractures of inferior wall/orbital floor

Question 5

what do orbital fractures often cause?

Answer 5

intra-orbital bleeding -> pressure on eye -> exophthalmos

Question 6

what is exophthalmos?

Answer 6

protrusion of eyeball

Question 7

what do tumors in the orbit cause?

Answer 7

exophthalmos

Question 8

which side of the eye offers a better approach for surgical operations and why?

Answer 8

lateral side - lateral wall of orbit does not reach as anteriorly as medial wall, so more of eyeball can be exposed from this side

Question 9

what can happen if you have loss of tonus of muscle in inferior eyelid?

Answer 9

causes lid to evert from surface of eye -> dry cornea + irritation of eye (not protected by eyelid) -> excessive lacrimal fluid

Question 10

what does a blockage of lacrimal apparatus drainage cause?

Answer 10

excessive lacrimal fluid

Question 11

what does infection/obstruction of ciliary gland ducts cause?

Answer 11

• sty/hordeolum

- chalazia

Question 12

what is a hordeolum/sty?

Answer 12

painful red supporative (pus-producing) swelling

Question 13

what is a chalazia?

Answer 13

cyst of the sebaceous glands of eye

Question 14

what does obstruction of a tarsal gland cause?

Answer 14

tarsal chalazion (inflammation) protruding toward eye and rubbing against it as you blink

Question 15

when you have bloodshot eyes, what is producing the red color you see?

Answer 15

dilated and congested vessels of conjunctiva (hyperemia)

Question 16

what causes hyperemia?

Answer 16

local irritation - dust, chlorine, smoke, etc.

Question 17

what is pinkeye?

Answer 17

inflamed conjunctiva aka conjunctivitis

Question 18

what do subconjunctival hemorrhages look like?

Answer 18

bright or dark red patches deep to and w/i the bulbar conjunctiva

(from rupture of small subconjunctival capillaries)

Question 19

where do the retina and optic nerve develop from?

Answer 19

optic cup - from the optic vesicle (bulge off of the embryonic forebrain)

Question 20

what develops from outer and inner layers of optic cup?

Answer 20

outer layer -> pigment cell layer of retina

inner layer -> neural layer of retina

Question 21

what is the intraretinal space? is it found in adult?

Answer 21

space that separates the developing layers of the retina in the embryo -> layers eventually fuse together

Question 22

what is the clinical significance of the intraretinal space?

Answer 22

sometimes neural layer isn’t firmly attached -> blow to eye can cause retinal detachment

Question 23

what usually causes detached retina?

Answer 23

seepage of fluid b/w neural and pigment cell layers of retina following trauma

Question 24

what do patients with detached retina complain of?

Answer 24

• flashes of light

- floaters (floating specks in front of eye)

Question 25

what does the pupillary light reflex test?

Answer 25

CN II - afferent limb | CN III - efferent limb

Question 26

what is the first sign of compression of the oculomotor nerve?

Answer 26

ipsilateral slowness of the pupillary response to light

Question 27

what is uveitis?

Answer 27

inflammation of the vascular layer of the eyeball (uvea) | -can cause severe impairement/blindness if untreated

Question 28

what causes edema of the retina?

Answer 28

increase in CSF pressure -> slows venous return from retina

Question 29

what is edema of the retina viewed as and what is it called?

Answer 29

viewed as swelling of optic disc -> papilledema

Question 30

what is presbyopia?

Answer 30

lens becomes harder and more flattened w/ age -> gradual reduction of focusing power of lens

Question 31

what are cataracts?

Answer 31

loss of transparency of the lens from areas of opaqueness (cloudiness)

Question 32

what does extracapsular cataract extraction involve?

Answer 32

removing lens but leaving the capsule of the lens intact to receive a synthetic intra-ocular lens

Question 33

what does intracapsular lens extraction involve?

Answer 33

removing lens and lens capsule and implanting a synthetic intra-ocular lens in the anterior chamber

Question 34

what is coloboma?

Answer 34

absence of a section of iris

Question 35

what are three things that cause coloboma?

Answer 35

- failure of choroid fissure to close properly - penetrating or non-penetrating injuries of eye - surgical iridectomy

Question 36

what is glaucoma?

Answer 36

when outflow of aqueous humor through the scleral venous sinus is significantly decreased -> pressure builds up in anterior and posterior chambers of eye

Question 37

what is the difference b/w open-angle and closed-angle glaucoma?

Answer 37

OA: drainage angle open; outflow blocked at trabeculae or scleral venous sinus CA: drainage angle closed by iris -> obstructs outflow

Question 38

what is hyphema?

Answer 38

hemorrhage w/i the anterior chamber of the eye

Question 39

what causes hyphema usually?

Answer 39

blunt trauma to eyeball

Question 40

what does the corneal reflex test?

Answer 40

- CN V1 | - CN VII

Question 41

what can foreign objects in the eye cause?

Answer 41

corneal abrasions -> sudden, stabbing pain in eye + tears

Question 42

what can sharp objects in the eye cause?

Answer 42

corneal lacerations

Question 43

what is Horner syndrome?

Answer 43

ipsilateral interruption of a cervical sympathetic trunk, causing: - miosis (constriction of pupil) - ptosis (drooping upper eyelid) - vasodilation (redness, higher skin temp) - anhydrosis (absence of sweating)

Question 44

what is diplopia?

Answer 44

double vision

Question 45

what can cause diplopia?

Answer 45

paralysis of one or more extra-ocular muscles

Question 46

what does oculomotor nerve palsy look like and why?

Answer 46

pupil down and out due to unopposed action of LR and SO

Question 47

what does abducent nerve palsy look like and why?

Answer 47

pupil fully adducted by unopposed action of MR

Question 48

what does blockage of the central artery of the retina cause and why?

Answer 48

instant and total blindness b/c terminal branches of the central artery are end arteries

Question 49

what does occlusion of a branch of the central vein cause?

Answer 49

slow, painless loss of vision