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Flashcards in The Eye Deck (55)
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1
Q

what are the 3 openings into the orbit

A

superior orbital fissure
inferior orbital fissure
opti canal

2
Q

what goes through the superior orbital fissure

A

occulomotor nerve, trochlea nerve, trigeminal (ophthalmic) and abducens

3
Q

what are the weakest parts of the orbit and why are they the weakest

A

the medial wall and floor

this is because they have air cavities next to them instead of bone

4
Q

what is an orbital blow out fracture

A

where trauma to the orbit causes a fracture of the floor of the orbit

5
Q

what does an orbital blow out fracture result in

A

swelling, double vision, anaesthesia over the cheeks

6
Q

why is there anaesthesia over the cheeks in a blow out fracture

A

as the intra-orbital nerve (trigeminal) runs through the floor of the orbit so is damaged

7
Q

what would be seen on a CT/X ray in a blow out fracture

A

the fractured floor
blood in the maxially sinus
orbital contents in the maxially sinus

8
Q

what are the 2 types of glands found in the eyelid

A

glands in the tarsal plates and glands at the hair follicles

9
Q

what happens if the glands at the tarsal plates are blocked

A

you get a meibomian cyst

10
Q

what happens if the glands at the eyelashes are blocked

A

you get a stye

11
Q

what are the tarsal plates

A

the fibrous skeleton giving the eyelids firmness and shape

12
Q

what is the orbital septum

A

it is a separation produced by the tarsal plates and tendon of levator palpebrae

13
Q

what is pre-septal orbital cellulitis

A

infection in the pre-septal orbit (space between the tarsal plates and the eyelid fat)

14
Q

what is post-septal cellulitis

A

infection the orbital cavity

15
Q

what does the orbital septum prevent

A

infection spreading between the pre and post septal orbit

16
Q

what are the complications of post-septal cellulitis

A

abscess

spreading to the cavernous sinus - this could then potentially spread to the brain

17
Q

what does the lacrimal gland do

A

produce tears to keep the conjunctiva and cornea lubricated

18
Q

where do tears drain

A

into the lacrimal punctum - this then goes through the lacrimal sac to the nasolacrimal duct

19
Q

what does the conjunctiva do

A

produces a mucus covering to help lubrication

20
Q

what makes up the outer layer of the eyeball

A

the sclera and cornea

21
Q

what covers the sclera

A

conjunctiva

22
Q

true or false: the conjunctiva covers the cornea

A

false

23
Q

what is subconjunctival haemorrhage

A

where a blood vessel in the conjunctiva suddenly bursts

24
Q

what makes up the middle layer of the eye

A

choroid, ciliary body and the iris

25
Q

what innervates the ciliary body

A

parasympathetics of the oculomotor nerve

26
Q

what happens when the ciliary body contracts

A

the 2 ciliary bodies come closer together (giving less pressure on the suspensory ligaments), this makes the lens fatter so light is refracted more

27
Q

where is aqueous humour produced

A

by the ciliary bodies

28
Q

how is aqueous humour circulated

A

once produced by the ciliary bodies it flows into the posterior and anterior chambers
it then drains through the iridocorneal angle to drain the canal of Schlemm and into the venous system

29
Q

what is the inner layer of the eye

A

the retina

30
Q

what is the arterial supply to the retina

A

ophthalmic branch of the internal carotid artery

31
Q

where do the ophthalmic veins drain to

A

cavernous sinus

32
Q

what nerve supplies sensation to the eye

A

(ophthalmic) trigeminal

33
Q

what nerve supplies motor to the eye

A

occulomotor, trochlea, abducens

34
Q

what nerve allows sensation to the eye

A

optic

35
Q

what us glaucoma

A

when the drainage of the aqueous humour is blocked causing an increase in intra-ocular pressure, damaging the optic nerve

36
Q

when looking at far objects, what causes light to refract the most

A

the Cornea

37
Q

describe the refraction of light when looking at close objects

A

the Cornea can’t refract light enough so the ciliary bodies contract to fatten the lens, allowing more refraction

38
Q

what is the accommodation reflex

A

what occurs when looking at closer objects:

  • pupils constrict
  • eyes converge
  • ciliary muscles contract
39
Q

why do the eyes converge when looking at closer objects

A

to prevent too much light from entering

40
Q

what is presbyopia

A

when the lens becomes stiffer so unable to refract light as well when looking at closer objects

41
Q

what is cataracts

A

when the lens and cornea are no longer transparent so light isn’t let through

42
Q

what is the purpose of the aqueous humour

A

supply nutrients and oxygen to the lens and cornea as these are avascular in order to remain translucent

43
Q

what are the intrinsic muscles of the eye

A
  • muscles of the iris (sphincter/dilator papillae)

- ciliary muscle

44
Q

what are the 6 extra-ocular muscles controlling eye movement

A

inferior rectus, superior rectus, medial rectus, lateral rectus, superior oblique and inferior oblique

45
Q

which of the extra-occular muscles are supplied by the trochlea nerve

A

superior oblique

46
Q

which of the extra-occular muscles are supplied by abducens

A

lateral rectus

47
Q

what are the functions of the extra ocular muscles

A
  • medial/lateral rectus = allows medial/lateral movement
  • inferior rectus = down and in
  • superior rectus = up and in
  • inferior oblique = up and out
  • superior oblique = down and out
48
Q

how do you test the superior oblique muscle

A

move eye medially and then down

49
Q

how do you test the inferior oblique muscle

A

move eye medially and then down

50
Q

how do you test the inferior rectus

A

move eye laterally and down

51
Q

how do you test the superior rectus

A

move eye laterally and up

52
Q

what will you see in occulomotor damage

A

pupil dilation
ptosis
eyes will go down and out

53
Q

what will you see in trochlea damage

A

up and in

54
Q

what will you see in abducens damage

A

eye will be pulled medially

55
Q

what is uveitis

A

inflammation of the choroid layer in the eye