Revision Flashcards
in the retina what do the rods do
are sensitive to low levels of light- night vision/ peripheral vision
in the retina what do the cones do
detailed vision (acuity), coloured vision
what are the ocular adnexae
extra oricular tissues- lids, lacrimal gland, lacrimal sac, naso-lacrimal duct
what is cranial nerve II
optic
what is cranial nerve III
oculomotor
what is cranial nerve IV
trochlear
what is cranial nerve V
trigeminal
what is cranial nerve VI
abducens
what is cranial nerve VII
facial
what is emmetropia
no refractive error in vision
what is hypermetropia
long sightedness- caused by eye being smaller than average
what is myopia
short sightedness- eye is bigger than normal
what is Astigmatism
blurred vision caused by the eye being shaped more like a rugby ball than a football
what is amaurosis
partial or total blindness without visible change in the eye
what is oscillopsia
when objects in the visual field appear to oscillate
what is diplopia
double vision
what condition causes the peripheral vision to deteriorate whilst central vision is maintained
glaucoma
what condition can headlight glare be a symptoms
cataracts
what condition cause central vision to deteriorate
macular degeneration
what is epiphora
excessive watering of the eye
how do you test visual function
visual acuity (clarity of vision), visual field, colour vision
what are the roles of the eyelids
tear film distribution, protects eyes, have glands that add to tear film
what is sclera show
when eyelids not covering iris, can see sclera above or below
what is ptosis
drooping or falling of the upper eyelid
what is the pupil sign that suggests horners
abnormally constricted pupil in eye with droopy eyelid
what controls the muscle LPS
CN III
what is the mullers muscle - action and innervation
fibres within LPS, holds open eye in F/F
sympathetically controlled
what is the role of the different parts of the orbicularis occuli
orbital part- squeezing of the eye, forced blink
palpebral part- normal blinking, reflex blink
what innervates the obicularis occuli
CN VII
what palsy affects obicularis occuli meaning you lose your reflex blink
bells palsy- presents with dryness and irritation
where are tears formed (three places)
fluid from lacrimal gland, oil from eyelid glands, mucosa from conjunctiva
what covers the inner surface of the eyelid
palpebral conjuncitva
what lines the eyeball
bulbar conjunctiva
what do the palpebral and bulbar conjunctiva create
a mucosal surface which allows tears to stick to eye
what makes up the cornea
epithelium bowmans membrane stroma descents membrane endothelium
what is the major refracting surface of the eye
cornea - bends the light onto the lens
why do you need glasses
misshapen cornea
what is a condition that clouds the lens
cataracts
what is the middle of the lens called
lens nucleus
what keeps the lens in place
zonules
does the cornea change shape in the accommodation reflex
no
describe the accommodation reflex
If looking at something in the distance cornea does enough light bending to focus light on the retina. If then go to close up cornea needs help from the lens to bend the light into focus. Spherical lens had more refractive power than a flat lens
To pull zonules ciliary muscles need to relax- this makes lens flat to see in distance. To see something close need spherical lens so need ciliary muscles to contract to relax the zonules
what is the natural shape of the lense
spherical
how does the lens shape change
contraction or relaxation of the cilliary muscle then relaxes or tightens the zonules
why do you need glasses as you get older to see close up
ciliary muscles doesn’t contract and zonules don’t relax aswell
what is the uvea
middle layer of eyeball, inbetween sclera and retina, formed from embryo uvea tissues, made up of choroid cilliary body and iris
what does the ciliary body do
makes aqueous
where is the choroid
underneath the retina - turns in to cilliary body and then iris
what is the role of the choroid
is extremely vascular- acts as a way to get blood to the avascular retina
what is the afferent pathway of the pupillary light reflex
optic nerve- chiasm- optic tract- BOTH pretectal nucleus- BOTH pretectal nucleus go to BOTH EWNucleii (each goes to two)
what is the efferent pathway of the pupillary light reflex
CN III (oculomotor) from EWN- synapses halfway at cilliary ganglion
what is the direct pupillary reflex
light in right makes right constrict
what is the consensual pupillary reflex
light in right makes left constrict
what will shining a light in the right eye tell you about the afferent pathway of the left
nothing
what is the RAPD pupillary reflex
(relative afferent pupillary defect)
subtle change in the afferent of one eye (optic nerve not working aswell)
how is RAPD tetsed
Swinging light test- by making maximal constriction in one eye and they switching to eye not working before has time to dilate properly will dilate a little bit as nerve not working at full capacity. If go back to other eye will go back to pin prick
do parasympathetics synapse close to or far from organs
close to
what is the path of the nerves from the eyeball to the brain
optic nerve chiasm optic tract lateral geniculate nuclei optic radiation occipital cortex
what side of occipital cortex will right visual field go to
left
same for left to right
lower to upper
upper to lower
what crosses at the chiasm
nasal visual field fibres (peripheral vision)
temporal remains on outside
what vision loss in a problem with the optic nerve
unilateral vision impairment (one side)
what vision loss in a problem with the chiasm (pituitary tumour)
bilateral hemianopia (loss of peripheral/ temporal fields)
what causes a homonomous vision loss (same side lost on both eyes)
problem after the chiasm
what causes a quadrantoanopia
problem with lobes after geniculate nuclei (e.g. parietal lobe)
what is the path of the lower visual field
hits upper retina, stay in upper fibres in nerves, chiams and optic tract, to nucleus, as high able to go in straight line to the occipital cortes to the parietal lobe
what is the path of the upper visual field
goes to lower retina, stay in lower part of nerve, chiasm and tract but are obstructed by the ventricles so to get to occipital cortex need to go around the front of the ventricle (in temporal lobe) (round the temporal ventricle)
what makes up the fibrous outer layer of the eye
sclera and cornea
what are the three coponents of the uvea
retina, choroid and iris
what makes up the iris
pigment cells and smooth muscle
what controls pupil size
sphincter pupillae constricts under parasympathetic stimulus
dilator pupilae dilates under sympathetic stimulus
what is the role of the ciliary body
secretes aqueous humor
(cilliary epithelium)
controls the shape of the lens
what is the path of light into the eye
tear film, cornea, aqueous humour of anterior chamber, pupil, aqueous humor of posterior chamber, lens, vitrous body (containing vitrous humour), retinal artery/ vein branches, ganglion cells axon, photoreceptors
why dont you blow your nose in blow out fractures
as might introduce nasal commensal- cause orbital cellulitis
what is the efferent limb of the pupillary reflex
oculomotor nerve and iris
what is the afferent limb of the pupillary reflex
retina, optic nerve, chiasm
how does a perforated blind fold test visual acuity
blocks divergent rays that need focusing, leaving only parallel rays that are focused already to strike retina- shows if vision bad cos need glasses if vision improved with this blindfold
what is the blind spot
the optic disc- part of retina with no photoreceptors, only axons joining to make optic nerve
what is the innervation of the lacrimal gland
parasympathetic CN 7
what are the components of CN III
somatic motor and parasympathetics
what nerve supplies sensation to the ala of the nose
ophthalamic division of the trigeminal nerve
what is the fovea
area of macula with greatest concentration of cones
where is optic disc always
nasal side of those pictures
what is the macula
area of greatest acuity- found in the centre of all four quadrants (centre of the retina)
when do you get vision changes in an eye pathology
when it affects the macula
what are the red dots in macular degeneration
haemorrhages (mild type only has haemorrhages)
when do you look at the macula in an osce
at the end as can be sore to look at the light
what do you look for in an osce in opthalmoscopy
cup, contour, vascular arcades, macula
(right eye use your right eye and stand on the right side)
red light, look into distance, dial to green 10= anterior chamber. dial down to 0 to into at the retina
mannequin heads commonly have CRAO or CRVO
list all the bones in the orbit
frontal, ethmoid, lacrimal, sphenoid, maxilla, zygomatic, palatine
list the key findingd in a 3rd nerve palsy
eyeball looks down and out droopy eyelid cant move eye medially or up pupil dilated, will struggle to constrict can also get headache
what pathology are you most concerned about
posterior communicating artery aneurysm
what is cupping and what causes it
loss of axons in the optic nerve, progressive thinning of the neuro-retinal rim (increasing the cup size)
found in glaucoma
what vision loss in cupping
tunnelling (brain fills in missing bits)
what is the treatment for a herpes simplex keratitis
aciclovir ointment or ganciclovir
what is a dendritic ulcer
herpes simplex keratitis
what do you never give to treat a dendritic ulcer
steroids- can cause corneal melt
what is ocular coherence tomography used for
wet macular degeneration
shows zones of fluid leakage
can be used for diabetic macular oedema
what does a CRVO look like
pale retina with a cherry spot macula- can see underlying arteries from choroid in macula
what causes sudden painless loss of vision with a number of CV risk factors
CRAO or CRVO
what is a hypopyon
pus fluid level in the eye
what are the signs of GCA
thickened wall of temporal artery, swollen disc
what is a hyphaema
fluid level of red blood cells in the anterior chamber- seen in blunt trauma
what type of hypersentivity is a corneal graft rejection
type 4
which cranial nerves are involved in afferent and efferent blink reflex
afferent: trigeminal V1 (nasocillary branch)- corneal sensation
efferent- facial nerve the orbicularis oculi
what is blepharitis
inflammation of the eyelids (v common, often chronic)
what are the types of blepharitis
anterior (seborric- flakey white scales, drandruff on eyelashes) (s. aureus- more erythematic, oedematous)
posterior (Meibomian (tarsal) gland dysfunction- too much secretion, associated with acne rosacea)
what are the symptoms of anterior blephritis
affects outer eyelid
- red lid margin
- scales, dandruff
- seborrheic dermatitis
- styes, ulcers, inflammation, distorted eyelashes, stains, keratitis
itchy red sore eyes, burning sensation, photophobia
what are the symptoms of posterior blepharitis
affects inner eyelid
- red, deep lid
- swelling
- dried secretions
- gritty eyes
- chalazia (eyelid cyst)
- acne rosacea
itchy red sore eyes, burning sensation, photophobia
what is the treatment for blephritis
lid hygiene (bathing, warm massage) topical chloramphenicol (short course) if acne rosacea- doxycycline incision/ currettage of chalazion furisidic acid
what is ectopion
lid margin rolls outward
caused by age, VII palsy
get watery eye
Tx= surgery
what is entopion
lid margin rolls inward- lashes against globe
caused by age
get irritation, red eye, abrasion
Tx= surgery
what is conjunctivitis - what can cause it
infammation of the conjunctiva
viral, bacterial, allergic
buzzwords: papillae and follicles
conjunctivitis
papillae- bacterial and allergic
follicles- viral and chlamydial
does conjunctivitis affect vision
not usually
what are the features of bacterial conjunctivitis
begins in one eye then spreads to other
acute onset
gritty eyes with purulent discharge (stuck together when wake up)
minimal pain
clear cornea
chemosis (conjunctival oedema) and lid oedema
papillae
what is the treatment for bacterial conjunctivitis
self limiting (14 days) to speed up: -chloramphenicol -penicillin if gonococcal -fusidic acid (can swab but dont usually need to)
who gets chlamydial conjunctivitis
adolescents and YA
beware the red eye in the neonate
what are the features of chlamydial conjunctivitis
slow onset red eye discomfort purulent discharge palpable pre auricular node corneal vascularisation follicles
what is the treatment for chlamydial conjunctivitis
topical erthyromycin
referal to GU/paediatrics
what viruses can cause viral conjunctivitis
adenovirus, herpes simplex + zoster, molluscum contagiosum
what are the features of adenovirus conjuctivitis
highly contagious follows URTI watery discharge chemosis lid oedema pseudomembrane follicles
what is the treatment for adenovirus conjunctivitis
self limiting
lubricants, hygiene
if corneal involvement/intense inflammation then can use topical steroid
what are the features of herpes simplex conjunctivitis
unilateral
affects eyelids + surrounding skin
dendritic corneal ulcer
palpable pre auricular node
what is the treatment for herpes simplex conjunctivitis
can be self limiting topical aciclovir (never steroids!!!)
what are the features of molluscum contagiosum conjunctivitis
unilateral
red eye that fails to improve
pearly umbilicated nodules
what is the treatment for molluscum contagiosum conjunctivitis
currettaging central lesion
short course topical prednisolone
is viral conjunctivitis water or dischargy
watery
what are the symptoms of corneal abrasion
severe needle like pain profuse watering decreased acuity photophobia circumcorneal redness hypopyon
what investigations into a corneal abrasion
fluoroscein drops + blue light
orange dye drops + blue light
what is the treatment for a corneal abrasion
topical anasthetic (oxybuprocaine)
chloramphenicol drops
steroids
(heals better without)
what is keratitis
corneal inflammation
what can cause keratitis
trauma, foreign body viral (adeno, herpes simplex) bacterial (staph, strep, pseudomonas, acanthamoeba (contact lenses) blephartitis fungal (trauma from vegetation)
what are the symptoms of keratitis
diffuse injection, red eye photophobia gritty eye decreased vision needle like pain epiphora (excess lacrimation) opacity
bacterial= hypopyon herpetic= v. painful fungal= slow growing
what investigations in keratitis
flouroscein, corneal scrape, gram stain
what is the treatment for keratitis
topical anaesthetic
ofloxacin if bacterial
aciclovir if herpetic
what is uveitis
inflammation of the uvea can be: anterior: iris and ciliary body -intermediate: ciliary body and choroid -posterior: back of eye, retina and choroid
what condition is common mistaken for conjunctivitis
uveitis
what is chorioretinitis
form of posterior uveitis
associated with cytomegalovirus and toxoplasmosis
what can cause uveitis
HLA-B27 gene: ankylosing spondylitis, reiters (reactive arthritis), UC, sarcoidosis)
infective (TB, syphilis, herpes zoster and simplex)
malignancy (leukaemia)
idiopathic
trauma
what are the symptoms of uveitis
unilateral pain decreased acuity photophobia red eye ciliary injection hypopyon (anterior) synchechiae (small irregular pupil) flashes and floaters
what is the treatment for uveitis
corticosteroid eye drops/ injections
cycloplegic mydriatic drops (dilate the eye)
rarely surgery/ immunosuppression
what is iritis
anterior uveitis
what are the features of anterior uveitis
red, painful eye photophobia injection normal/blurred vision cells, keratic precipitates hypopyon
what is the treatment for anterior uveitis
topical dexamethasone
mydriatics (pupil dilator)
what is episcleritis
inflammation below the sclera, usually idiopathic, sometimes associated with gout
what are the symptoms of episcleritis
acute onset mild pain/ discomfort tender globe, achy eye blue sclera normal acuity usually associated with a nodule
what is the treatment for episcleritis
self limiting
topical/systemic NSAIDs
what is scleritis and what is it associated with
severe inflammation throughout entire thickness of sclera
V rare, more common in women
associated with RA
what are the symptoms of scleritis
sub acute severe boring eye pain that radiates to forehead, brow and jaw local/ diffuse red eye violoceous hue (purple due to deep injected vascular plexus) tender globe watering photophobia gradual decrease in vision
what is the treatment for scleritis
oral NSAIDs/steroids
