Eye anatomy and visual pathways and examination Flashcards
state the 6 extraocular muscles
superior, inferior, medial and lateral rectus
superior and inferior oblique
what nerves inervate the eye and their function 3
CN3- superior, inferior, medial and lateral rectus
CN4- superior oblique
CN6-lateral rectus
anatomty of the outereye
eyelid
conjuntiva and sclera
iris
pupil [39]
anatomy of inner eye
[40]
define the conjuntiva/sclera
white outer coat of the eye
define the cornea
clear front window of the eye which transmits and helps focus light
define the iris
coloured pat of the eye
-helps control how much of light enters the eye
define the pupil
dark centre at middle of iris
-reacts to amount of light available
define the lens
focuses light rays onto the retina
-normally transparent
clouding of lens=cataracts
define vitreous
clear gel filling central cavity of the eye
define the retina
layer of nerve cells lining the back of the eye
-contain photo receptors
define the two types of photoreceptors
rods
-function in dimmer light (black and white)
cones
-brigher light, high acuity tasks (reads)
-sees colour
CONES SEE COLOUR
function of the retina
light srikres retina
-initates cascade of chemocal and electircal event s
-triggers nerve impulses that are sent to optic nerve
on to visual cortex via visual pathways
define the choroid
layer at back of eye between retina and sclera
contains blood vessels
assoc w macular degentation
define the macula
located near centre of retina
-responsibole for detailed central vision
-deteriorates with age
assoc w ARMD
define the optic nerve
CN2
> 1mil ganglion cells
transmits visual info via visual pathways to visual cortex
how does vision work (3 basic steps
optics of eye create image on retina
photoreceptors (rods and cones)
-convert into neural impulses
passed on via optic nerve & visual pathways to visual cortex (occipital lobe)
how are central and peripheral vision tests
centra- visual acutiy -snellens or logmar
peripheral-visual fields test - click button light thing
overveiw of visual feld defects
[41[
what visual feild defect do you get with an optic chiasm tumour
bitemporal hemianopia
what visual field defect do you get with an occipital cortex lesion
contralateral homonymous hemianopia
aspects of an ophthalmology h exam 6
Basic Eye Exam
Visual acuity
Pupils
Visual Fields
Eye Movements
External Eye/Slit lamp
Ophthalmoscopy
aspects of an ophthalmology history 8
PC
HPC
past ocular history
past medical history
drug history
family history
social history
systemic enquiry
red flag ocular syx 7
floaters/flashing lights
haloes
headaches
-temporal
-jaw claudication
-worse with bending
repeated transient visual loss
aspects of past occular hisotry 6
what is ptx normal vision
similar syx before
other eye conditions
previous eye operations
-cataracts
-corneal graft
-glaucoma surgery
ocular motility disorders 6
neurolgocaial
-microvacular iscchaemia (HTN,DM)
-aneurysm
-CVA
-raised ICP
NMJ
-MG
Mechanical
-thyroid eye disease
-orbital fracture
what gives the blood supply to the eye and where does it branch from
first branch of the internal carotid
-gives rise to the ophthalmic artery
-this comes of just before reaching the circle of willis
ophthalmic artery then gives off a branch for the central retinal artery
other arteries involved in the eye
[43]
anatomy of the neuronal pathways for the pupils
[44]
aspects of a visual loss history 8
Pain
Duration
Degree of vision loss
Permanent or transient - periodicity
Central or peripheral loss
Progression – getting better or worse
One or both eyes
Associated symptoms (flashes and floaters, pain, redness)
