Opthal Flashcards
what is glaucoma
damage to the optic nerve cause by raised intraocular pressure due to blockage in aqueous humor trying to escape the eye
types of glaucoma
acute angle closure
opne angle
norma intraocular pressure
10-21 mmhg
open angle glaucoma pathophysiology
reduced flow of aqueous humor through the trabecular meshwork
acute angle closure glaucoma pathophysiology
the iris is pushed forward and seals off the trabecular meshwork so aqueous humor cannot drain at all
how is optic disc cupping identified
the optic cup:optic disc ration is usually 0.5, if the optic cup takes up more than half the disc this is raised IOP
risk factors for open angle glaucoma
age
family hx
near sightedness- myopia
what is myopia
near sightedness
glaucoma symptoms
gradual loss in peripheral vision (tunnel vision)
haloes around lights especially at night
blurred vision
headaches
how is IOP measured
tonometry
what does gonioscopy measure
the angle between the iris and cornea
what IOP warrants mx in glaucoma
> 24 mmhg
mx glaucoma
laser trabeculoplasty
prostaglandin analogue eg latanoprost to increase uveoscleral outflow
beta blocker and carbonic anhydrase eye drops to reduce aqueous humor production
trabeculectomy if these are not effective
what do prostaglandin analogue eye drops do in glaucoma and give and example
latanoprost
reduce uveoscleral outflow
what do beta blocker eye drops do in glaucoma and give an example
timolol
reduce aqueous humor production
what do prostaglandin analogues do in glaucoma and give an example
dorzolamide
reduce aqueous humor production
what ethnicity is at higher risk of open angle vs acute angle closure glaucoma
open angle= black afro caribbean
acute angle closure= chinese and east asian
what medications can precipitate acute angle closure glaucoma
andrenergic eg noradrenaline
anticholinergic eg oxybutynin
TCA eg amtriptyline
acute angle closure glaucoma symptoms
acutely painful red eye
hazy cornea
headache
nausea
vomitting
blurred vision
haloes around lights
hazy cornea
mid dilated pupil
fixed size pupil
inital management of acute angle closure glaucoma
lay the patient flat without a pillow
pilocarpine eye drops
acetazolamide
analgesia and antiemetics
moa pilocarpine eye drops
act on muscarinic receptors causes pupil constriction and ciliary muscle contraction to increase flow of aqueous humor
acetazolamide moa
carbonic anhydrase inhibitor- reduces production of aqueous humor
definitive management of acute angle closure glaucoma
laser iridotomy
symptoms of AMD
gradual loss of central vision- scotoma
reduced visual acuity
wavy appearance of straight lines
most common cause of blindness in the UK
AMD
what is seen on fundocscopy in AMD
drusen
what test is used in AMD to assess distortion of straight lines
amsler grid
what is the pathophysiological difference between wet and dry AMD
in wet there is neovascularisation
what is used to diagnose AMD
optical coherence tomography
slit lamp exam
fluorescein angiography
what ix is used to differentiate between wet and dry AMD
fluourescein angiography
mx AMD
dry- avoid smoking, control BP, vitamin supplementation
wet- anti VEGF injections once a month
features of background diabetic retinopathy
microaneurysms
retinal haemorrhages
hard exudates
cotton wool spots
features of pre proliferative diabetic retinopathy
venous beading
multiple blot haemorrhages
intraretinal microvascular abnormality
proliferative diabetic retinopathy
neovascularisation
vitreous haemorrhage
what is diabetic maculopathy
exudates in the macula
macular oedema
cotton wool spots arise due to
nerve damage
management of diabetic retinopathy
non proliferative= monitoring and diabetic control
proliferative=
pan retinal photocoagulation
anti VEG-F injections
surgery if severe
treatment for macular oedema in diabetic retinopathy
intravitreal implant containing dexamethasone
complications of diabetic retinopathy
vision loss
retinal detachment
vitreous haemorrhage
features of hypertensive retinopathy
silver wiring- thickening of arterioles
AV nipping- compression of veins due to thickened arterioles
cotton wool spots
heard exudates
retinal haemorrhages
papilloedema
classification system for hypertensive retinopathy
keith wagner
keith wagner classification
stages of hypertensive retinopathy
1- mild narrowing of arterioles
2- focal constriction of blood vessels and AV nicking
3- cotton wool patches, exudates and haemorrhages
4- papilloedema
what feature on examination indicates cataracts
loss of red reflex
what are symptoms of cataracts
slow reduction in visual acuity
progressive blurring of vision
colours becoming faded
starbursts around lights especially at night
complication of cataract surgery and how its managed
endopthalmitis- inflammation of inner contents of eye due to infection, can lead to vision loss
mx by intravitreal abx
how does the pupil contract
parasympathetic nervous system fibres travel along the optic nerve and use acetylcholine to constrict the pupil
how does the pupil dilate
sympathetic nervous system fibres use adrenaline as a neurotransmitter to dilate the pupil
causes of a dilated pupil
congenital
stimulants eg cocaine
anticholinergics eg oxybutynin
third nerve palsy
holmes adie pupil
raise IOP
acute angle closure glaucoma
cause of a constricted pupil
horner syndrome
cluster headache
argyll robertson pupil
opiates
nicotine
pilocarpine
third nerve palsy triad
ptosis
mydriasis
down and out position
what happens to pupil in third nerve palsy
dilated/ mydriasis
what muscles of the eye does the third nerve suply
parasympathetic
what does third nerve palsy with sparing of the pupil inidicate
microvascular cause eg diabetes, hypertension, ischaemia
causes of a third nerve palsy
tumor
cavernous sinus thrombosis
posterior communicating artery aneurysm
raised IOP
horner syndrome triad
ptosis
miosis
anhydrosis
how to differentiate between locations of horners syndrome
where anhydrosis occurs
central= anhydrosis of arm, trunk and face
pre ganglionic= anhydrosis of the face
post ganglionic= no anhydrosis
central causes of horners syndrome
4 s
stroke
sclerosis (MS)
swelling (tumors)
syringomyelia
pre ganglionic causes of horners
5 ts
tumor (pancoast)
trauma
thyroidectomy
top rib (cervical rib)
post ganglionic causes of horners syndrome
4 cs
carotid aneurysm
carotid artery dissection
cavernous sinus thrombosis
cluster headache
pneumonic for cause of horners syndrome
4s 4t 4c
central= 4s
pre ganglionic= 4t
post ganglionic= 4c
stroke
sclerosis
syringomyelia
swelling
trauma
tumor (pancoast)
top rib
thyroidectomy
cavernous sinus thrombosis
carotid aneurysm
carotid artery dissection
cluster headache
how to test for horner syndrome
cocaine eye drops dont dilate the pupil
adrenaline eye drops dilate the pupil
holmes adie pupil and cause
damage to post ganglionic parasympathetic fibres
dilated pupil
sluggish to react to light
responds to accomodation
slow to dilate after being constricted
argyll robertson pupil is associated with
neurosyphillis
argyll robertson pupil presents as
a constricted pupil that accomodates but doesnt react to light
blepharitis mx
warm compresses and cleaning of eyelid margins
blepharitis is due to dysfunction of
meibum glands
how to differentiate stye and hordoleum internum
hordoleum internum is deeper, more painful and points towards the eyeball underneath the eyelid
what is preseptal cellulitis
periorbital cellulitis
difference between peri orbital and orbital cellulitis
how to differentiate
peri orbital involves eyelid and skin infection in front of the orbital septum
orbital involves tissues behind the orbital septum
differentiate by CT
causes of painless red eye
conjunctivits
episcleritis
subconjunctival haemorrhage
causes of painful red eye
acute angle closure glaucoma
scleritis
anterior uveitis
corneal abraison
keratitis
foreign body
traumatic or chemical injury
who needs urgent referral when they have conjunctivitis
neonates under a month
mx conjunctivitis
cloramphenicol or fusidic acid eyedrops if bacterial
antihistamine if allergic
otherwise self resolving
conditions anterior uveitis is associated with
seronegative spondyloarthropathies
IBD
sarcoidosis
bechets disease
anterior uveitis sx
painful red eye
reduced visual acuity
photophobia
excessive lacrimation
ciliary flush
miosis
hypopyon
what is a hypopyon
a collection of white fluid in the anterior chamber of the eye
seen in anterior uveitis
mx anterior uveitis
steroids
cycloplegics
cycloplegic eye drop examples and use
cyclopentolate or atropine
used in anterior uveitis to dilate the pupil and reduce pain due to ciliary muscle spasm
