The orbital cavity: eye and lacrimal apparatus Flashcards
The medial orbital wall consists of four bones
the frontal process of the maxillary bone: the lacrimal bone, the orbital plate of the ethmoid bone, and the lesser wing of the sphenoid bone.
SO attaches to orbit
difference between the axis of the eyeball (parallel) and axis of the orbit ( divergent)
axis of the eyeballs stragtiht through the eye straight whereas axis of the orbit is more triangular at base of pyramid from the base of pyramid
roof or orbit formed by
frontal bone
inferior wall of orbit formed by
maxilla and zygomatic
medial wall of orbit
SELMn sphenoid ethmoid and lacrimal and maxilla
lateral wall
zygomatic bone and sphenoid greater wing
apex id the opening to
optic canal
what muscles close the eyelids
inneravtion
orbicularis oculi
facial N. -7 hook close
what muscle lifts the upper eyelid to open eyes
levator palpeerde superioris
oculomotor nerve - hold eye open
droopy eyelid
interrupted sympathetic supply to mullers muscle
or ocuclomot nerve due to levator palpeerde superioris
what glands lubricate eyelash lids
tarsal glands - long sebaceous glands
lacrimal gland is made up of two bits the larger orbital gland and smaller palpebral gland. 12 ducts drain into the superior conjunctival fornix what nerve supply to this gland
7th cranial nerve initially and jumps onto the maxillary nerve and zygomatic branch then finally lacrimal branch
Vivian nerve/greater petrosal nerve
contraction of lateral rectus
moves eye laterally
contraction of superior rectus muscle
moves eye up and medially
suprieiro oblique contraction
eye down and out /laterlly
incyclptrosion
inferior oblique up and out
abduction and elevation and excyclotorsion
testing the eyes
SR
look laterally and up
testing IR
look laterally and down
testing LR
laterally
testing MR
look medially
IO testing
look medially and up
SO testing
medially and down
right eye normal left eye is very medial what is the problem
palsy to laterally rectus muscle as there is no muscle tone pulling the eye laterally therefore the abducnets nerve had been palsied
left eye normal
right eye is laterally and depressed - down and out what nerve palsy
also droopy eyelid lost levator plapeioirs
pupils dilated too - parasymptathic nerve repsonse lost
oculomotor never nerve injury
damage to IO and IR
right eye fine
left eye up and medially
probably with head tilt
trochelar nerve injury - superior oblique
3 layers of the eyeball
fibrous
vascular
inner layer
what is contained in the fibrous layer of th eye
sclera and cornea
Papilledema
no pain §
Papilledema is swelling of your optic nerve, which connects the eye and brain. This swelling is a reaction to a buildup of pressure in or around your brain that may have many causes. Often, it’s a warning sign of a serious medical condition that needs attention, such as a brain tumor or hemorrhage
In patients with papilledema, vision is usually not affected initially, but seconds-long graying out of vision, flickering, or blurred or double vision may occur. Patients may have symptoms of increased intracranial pressure, such as headache or nausea and vomiting. Pain is absent.
junction where sclera meet the cornea
limbus
treatment fro retinal detachment
scleral buckle
sclera icterus - due to hepatic failure and jaundice
yellow eyes - bilirubin build up
red blood shot eye due to to
vessel dilating - sign of allergic reaction or irritation
what is conjunctiva
tissue that lines the inside of the eyelids and covers the sclera
corneal abrasion - scratch on eye
most people recover in few days
keratoconus
sx
cornea forms a cone the black bit of the eye looks like it is dropping eye
cannot focus as well centrally
vascular layer of th eye is composed of
choroid , ciliary body and iris
iris is like a diaphragm
ciliary body controls shape of
the lens
nerve supply of ciliary muscles
CN3 - para supply and ganglion close to eyeball
ciliary muscle does what
lgimanets pull lens out
when it contract it relaxes suspensor ligaments and the lens become more spherical
ctatcarct surrgyer
phacoemulsifcation
inside of lens stopped out and replaced with a plastic one
parasympathetic stimulation causes circular muscle to contract - constrict
synpathetic stimulation causes radial muscle to contact - dilate
all consoled by what
iris
horners syndorme
ptosis - one eye ( two could be problem with mysathneai)
anhidrosis and misois ( constructed pupil)
constricted pupil , misois and ptosis
drugs fro dilating pupils - mydriatic medications
tropicamide and atropine ( parasympathetic antagonist)
gives opthalmogist a better view of retina and optic nerve
contracts the radial pupil smooth muscle making it much bigger and clearer to see
inner eyes contain the retina
rods and cones what is the difference
rods see black and white - used at night - sensitive to low light conditions - rods are mainly round periphery of your retina so look out the corner of your eye
cones - work ind daylight conditions - colour and tightly packed in the centre of the retina to get high reolstuion in the centre of your eye
colour vision evolved when we ate fruits seeing red apple against leaves
3cones
blue - chromosome 7
red and green - x chrosmoem - which is why you get red green colourblindness most commonly in males - inherited from the mum
centre of retina called
macula - got a yellow pigment
retina ends at ora serratus at the peripheries
under light ophthalmoscope where do you find the macular and optic disc
macular is dead centre and optic disc is towards the right edge - medially aspect of the eye
age related macular degeneration - blinds rare
sx
forms a cloud in the centre of the pcitreu
yellow drusen - loss of sensory cells and get colour vision loss and lose centra vision
wet and dry
dry - build uo
wet - get new vessel formation - treated with lcuentivez stop progression
retinitis pigmentosa
dangerous for driving
ant chamber and post chamber either side of the
iris
what fluid in ant chamber
aqueous humour
what fluid in post chamber
vitreous chamber
has hyaloid canal - can get a vessel
if it drops off and forms floaters in the ey - look like colourless worms of hair
pending retinal detachment
eye floaters due to vitreous humour
vitrectomy procedure
aqueous humour ha high turn over
too high build of aqueous humour causes what
glaucoma - blockage to canal of schlem
Glaucoma Causes: 1. Insufficient drainage of Canals of Schelm then veins 2. Iridocorneal angle could narrow Treatment: 1. Drugs improving the flow at the Canals of Schelm (drugs similar to prostaglandins) 2. Decreasing aqeous humour production (beta
-adrenergic
receptor antagonists) 3. Vasoconstriction of arteries of the ciliary body (epinephrine) 4. Insertion of glaucoma drainage implants
