Vascular occlusions Flashcards
Where do vascular occlusions occur ?
- tend to be unilateral so occur in one eye
- very rare bilateral
What are the symptoms of vascular occlusions ?
- Unilateral sudden painless loss of vision
- May go unnoticed by elderly patient
Who does the vascular occlusions affect ?
-Typically affects the elderly
Not exclusively
What is central retinal artery occlusion ?
- Obstruction of central retinal artery by embolus or thrombus
- Usually below surface of optic nerve head
What is the epidemiology of the central retinal artery occlusion ?
- Onset mid-sixties
- Male to female ratio 2:1
- Rare (incidence 1.9 in 100,000 in U.S.)
What does the px present with when have central reitnal artery occlusion?
- Sudden painless profound loss of vision
- May be preceded by transient loss of vision
What is this transient loss of vision called ?
-Amaurosis Fugax
what is amaurosis Fugax?
- transient obscuration of retinal artery by embolus
- transient ischaemic attack (TIA)< 24 hours
- causes a sudden monocular loss of vision
- painless
- ‘like blind coming down’
- clears slowly in reverse direction
- repetitive ( can happen 2 or 3 types in 24 hours)
what is the optometric management of Amaurosis Fugax?
- refer to G.P. urgently after excluding giant cell arteritis
what are the symptoms of central retinal artery occlusion ?
. visual acuity usually CF ( count fingers ) to LP ( light perception )
. exceptions cilio-retinal artery (25%)
what are the early signs of central retinal artery occlusion?
1- pale oedematous retina especially at the posterior pole
2- cherry red spot at macula
. macula blood supply from choroid via posterior ciliary arteries
. surrounding retina pale in comparison
. macula is thinner - so transparency
- arterial attenuation - thinner artery
- segmentation - changes at artery
- emboli may be seen
- RAPD- do swinging light test
what are the late signs of central retinal artery ?
. optic disc atrophy
. arterial attenuation and segmentation
. VA usually remains markedly reduced despite treatment
what are the causes of central retinal artery occlusion ?
- embolus > thrombus
- embolus-carotid artery and heart disease
. cholesterol crystals from carotid arteries
. platelet-fibrin emboli arising from large vessel stenosis
.calcific emboli arising from carotid valve stenosis
- thrombus
. blood clot
. stenosis
what is embolus caused by ?
- cholesterol crystals from carotid arteries
- platelet-fibrin emboli arising from large vessel stenosis
- calcific emboli arising from carotid calve stenosis
what is thrombus caused by?
- blood clot
- stenosis of carotid artery
what are the risk factors central retinal artery occlusion?
- systemic hypertension
- diabetes mellitus
- hyperlipidemia
- carotid artery disease
- coronary artery disease
- TIA/CVA
- giant cell arteritis
- tobacco smoking
what is the optometric management of central retinal artery occlusion?
- measure visual acuity
- check pupils
- urgent referral to eye casualty (if < 12 hours old)
- first aid - aim to dislodge embolus
. ocular digital massage
. breathe into paper bag ( increased CO2 levels) - aim is to get embolus to move through the ocular system to unblock
what is the ophthalmological management of central retinal artery occlusion?
1- reduce IOP
. anterior chamber paracentesis
. intravenous acetazolamide and ocular massage
2-dilation of arteries . ocular massage . retrobulbar vasodilator drugs . inhalation of carbogen . lysing of embolus/thrombus . systemic anticoagulants
3- investigation of cause
. increased mortality with presence of emboli
how prevalent is central retinal artery occlusion: with cilio-retinal artery ?
- 20% population have cilio-retinal artery
what is branch retinal artery occlusion ?
- occur in seventh decade
- results from embolus
- 90% temporal retinal arteries
- sudden painless loss of vision
. hemifield or sector loss of vision
. altitudinal VF loss- superior visual field defect - prognosis good
. 74%-V/A 6/12 + VF defect
what is central retinal vein occlusion ?
. obstruction of central retinal vein below lamina cribosa
what is the epidemiology of central retinal vein occlusion?
- more commonly affect older people in their mid-sixties , but can also occur in younger patients
- male to female ration equal 5.2 in 1,000
what is the presentation of central retinal vein occlusion?
- sudden painless loss of vision
- variable deficit
- may go unnoticed
what are the signs of central retinal vein occlusion ?
. 'blood and thunder' . flame-shaped haemorrhages in all 4 quadrants . disc oedema . venous dilation . multiple cotton wool spots . RAPD likely
what are the two types of central retinal vein occlusion ?
- Non-ischaemic
2. ischaemic
what are the signs of non-ischaemic central retinal vein occlusion?
. VA is better than 6/60 . RAPD is not marked . less haemorrhages . no/few cotton wool spots . 20% become ischaemic
what are the signs of ischaemic central retinal vein occlusion?
. visual acuity <6/60 less . Marked RAPD . extensive haemorrhages in 4 quadrants . disc swelling . venous tortuosity . cotton wool spots
what are the central retinal vein occlusion complication ?
- neovascular changes: new blood vessels in the iris or within the trabecular meshwork
what do neovacular changes cause ?
- neovascular glaucoma
what is neovascular glaucoma ?
. caused by retinal hypoxia . angiogenesis substance released . new vessels develop in angle . fibrovascular membrane develops across trabecular meshwork . early intervention required . intractable and devastating
what are the systemic causes of central retinal vein occlusion ?
- systemic hypertension
- diabetes
- arteriosclerosis
- hyperviscosity syndromes
- oral contraceptive pill
what are the ocular causes of central retinal vein occlusion?
- raised IOP>30mmHG
what are the optometric management of central retinal vein occlusion?
- check IOP
- Normal IOP
. refer to ophthalmologist within 2 weeks
. refer to GP for full cardiovascular investigation - if IOP>30mmHG
. refer to ophthalmologist within 24 hours and refer to G.P for full cardiovascular investigation
what is the ophthalmological management of central retinal vein occlusion ?
- flurorescein angiogram
- to determine if ischaemic or non-ischaemic - new vessels
- pan-retinal photocoagulation
- intra-vitreal anti-VEGF? - macula oedema
- intravitreal steroids
e. g. triamcinolone acetonide
- intravitreal anti-VEGF ( e.g. lucentis )- TO REDUCE INFLAMMATION
. investigation and treatment of underlying cause
what is branch retinal vein occlusion?
- hemi field visual loss
- obstructed vein dilated and tortuous
- retinal oedema
- scattered superficial and deep retinal haemorrhages
. respect the horizontal midline, confined to one quadrant
what are the causes of branch retinal vein occlusion?
changes in systemic cardiovascular changes
what is the optometric management of branch retinal vein occlusion ?
- measure visual acuity
- fundus examination
. dilated BIO - pupil reactions
- visual field
- refer to GP cardiovascular investigation
- ophthalmological referral
what is the ophthalmological management of branch retinal vein occlusion?
. fluorescein angiogram
. grid laser coagulation if macula oedema persistent
. retinal neovascularisation refer in BRVO
. prognosis good if treated VA > or equal 6/12
25% will have VA < 6/60
what is anterior ischaemic optic neuropathy ?
. ischaemia of anterior optic nerve head
. occlusion the posterior ciliary arteries
what is the epidemiology of anterior ischeamic optic neuropathy ?
- almost exclusively after the age of 50 years
- incidence 18 per 100,000 after 50 years
- women > men ( 2:1 )
what are the two types of anterior ischaemic optic neuropathy ?
- arteritic (A-AION)
- non-arteritic (NA-AION)
what is arteritic ( A-AION)
- 5-10% cases
- older age group ( mean 70 years )
- associated with temporal arteritis
what is non-arteritic ( NA-AION)
- 90-95% cases
- younger age group ( mean 60 yrs)
what happens in A-AION?
- profound loss of vision
- pale oedematous optic nerve head
- splinter haemorrhages
- RAPD
- risk of visual loss in other eye, myocardial infarction, renal failure, aortic aneurysm
what is temporal arteritis ?
- giant cell arteritis
- inflammation of medium and large arteries
what are the symptoms of temporal arteritis ?
- headache . normally constant . gradual onset to a diffuse severe aching . superficial scalp tenderness- temporal . worse at night and in the cold
. general malaise, weight loss, jaw claudication , amaurosis fugax
. polymyalgia rheumatica
what are the presentation of NA-AION?
- sudden loss of vision
. mild to severe
. usually on waking
. vision loss either static or progressive - 20% lose vision in other eye within 5 years
- at risk disc
- associated with hypertension diabetes
what are the signs of NA-AION ?
- oedematous optic nerve head
. diffuse or segmental
. hyperaemic or pale - visual field loss
. usually altitudinal - contralateral eye
. small disc
. small or absent cup
. subsequent optic atrophy
-33% left with near normal V/A
what is the optometric investigation of AION?
. VA, pupils, colour vision, VFs, IOP
. dilated fundus examination
what is the optometric management of AION?
. emergency referral to casualty
. contact ophthalmologist
what is the ophthalmological investigation of AION?
- blood tests
- temporal artery biopsy
- scan ( Doppler, MRI)
what is the optometric management of AION?
- aspirin, treatment of cardiovascular problem
- if arteritic high doses of systemic steroids for years
