Retinal Vascular Disease 1

Different types of blood vessels?

arteries, arterioles, capillaries, venules, veins

What does microvascular mean?

comprised of capillaries

What does macrovascular mean?

comprised of all other blood vessels

Key blood vessels in the Ocular Blood Supply?

Internal carotid artery

Ophthalmic artery

Posterior ciliary arteries

Central retinal artery

Other arteries that feed into anterior ciliary arteries

What are the two circulations of the eye

Central retinal artery and Ciliary arteries

What do the Central retinal artery / vein supply?

inner retina to OPL

What do the posterior and anterior ciliary arteries / vortex veins supply?

Uvea ,

outer retina to OPL (Photoreceptors)

What do the short posterior ciliary arteries supply?

Posterior uvea

Anterior optic nerve

why is the CRA described as ‘end arteriole’

there are no channels between artierioles so if there isa blockage anything distal to it will be susceptible to ischaemic damage

why is ischaemic changes rare in the uveal circulation

its robust so there are any intercommunicating channels so that any bloackage can be bypassed without interferring with the overall oxygenation o the tissues

4 Key features of retinal arterioles?

cross OVER veins, Share outer coat (adventitia), Site of BRVO, site of Arteriolosclerotic changes

How do venules compare to arterioles?

Darker red

Wider

More tortuous

Capillaries structure?

Wall is single cell thick, Thick basement membrane, Pericytes, Astrocyte foot processes, Selectively permeable

How is Fundus photography / SLO used to investigate of ocular vascular disease

Retinal vasculature, Haemorrhage, Exudates / Cotton wool spots

How is Fluorescence angiography used to investigate of ocular vascular disease

• Structural integrity of vessels

• Dynamic integrity of circulation- leaking of blood

• Fluorescein: retinal circulation- capillary beds

• Indocyanine green: choroidal circulation- any new abnormal blood vessels arising from choroid

How is OCT used to investigate of ocular vascular disease

Oedema, Macula

How is OCT angiography used to investigate of ocular vascular disease

Retinal circulation, Work in progress

Congenital anomalies of retinal blood vessels?

Congenital vascular tortuosity,

Anomalous blood vessels,

Bergmeister's papilla (hyaloid artery remnant at optic disc),

Cilioretinal artery

Telangiectasia

Coats disease

Key features of Cilioretinal artery

• From short posterior ciliary arteries

• Same supply as choroid

• Common (20 - 30%)

• Vascular pathology

What is Telangiectasia

abnormal dilation of a blood vessel

types of telangiectasis for eye

• Congenital retinal telangiectasia

• Idiopathic juxtafoveal retinal telangiectasia

Key features of Coat's disease?

• Rare

• Children (boys)

• Squint

• Leukokoria / yellow or absent red reflex

• Reduced vision

• Dilated abnormal leaky vessels

• Gross exudate,

• Exudative retinal detachment

• Progressive,

• Treatment difficult

Result of acquired vascular disease?

cell damage and death (necrosis)

What causes cell damage and death in acquired vascular diseases?

Ischaemia and infarction due to disordered circulation because of damaged blood vessels

Vascular diseases within the lumen?

• Haemodynamic: hyperviscosity and sluggish circulation

• Thrombosis: in situ blood clot in a blood vessel e.g chlosterol

• Embolus: abnormal mass (including a thrombus) travelling in bloodstream

Vascular disease within vascular wall?

• Thinning and increased permeability, leakage

• Oedema

• Haemorrhage.

• Thickening - Arteriosclerosis • Atherosclerosis • Spasm • Inflammation.

• Dilatation • Tortuosity • aneurysm

Vascular disease external to vessel?

• Compression

• IOP / glaucoma

Risk factors for vascular disease including ocular vascular disease

Hypertension • Diabetes mellitus • Hyperlipidaemia • Obesity • Smoking • Age • Haematological = blood disorders

What blood disorders can be a risk factor for vascular disease?

• Hyperviscosity e.g. polycythaemia, leukaemia

• Increased clotting

• Anaemia

What is Atherosclerosis

fatty deposits in arterial wall

Large / medium sized arteries

leads to Thrombosis • Embolism

What is Arteriolosclerosis

• Thickening of walls / narrowing of lumens of small arteries and arterioles e.g. retina

Key features of Hypertensive retinopathy

• Systemic hypertension - BP consistently > 140/90

• Chronic changes - Accelerated ageing changes

• Arteriolosclerosis - Accentuated light reflex: 'silver wiring' - Arteriovenous crossing changes so nipping - Focal arteriolar narrowing

• Changes do not significantly correlate with hypertensive control

• Common

What are features of Accelerated hypertension/ malignant hypertension

• Recent, often severe, elevation in baseline BP associated with target organ damage: CNS (including eye), CVS and renal system

• Medical emergency

• Due to damage (fibrinoid necrosis) of small arteries, arterioles and capillaries

• due to increased permeability from fibrinoid necrosis causing leakage from damaged blood vessels causing Nerve fibre haemorrhages (flame-shaped) or Exudates e.g. macular star

• Retinal ischaemia / infarction - Cotton wool spots

• Disc oedema

• Rare

What is an aneurysm?

pathological dilatation of a blood vessel

Key features of Retinal Macroaneurysm?

• Hypertension

• Arterial disease

• Bifurcations of arterioles

• Leakage, retinal oedema and exudate

• May be asymptomatic

What is Transient retinal ischaemia: amaurosis fugax?

fleeting loss of vision, A form of "transient ischaemic attack

Sx of Transient retinal ischaemia?

transient loss of vision

• typically all or part of their vision

• returns to normal after a few seconds or minutes.

What is Transient retinal ischaemia an important indicator of?

• Systemic vascular disease

• Carotid artery disease

• Retinal emboli

• Giant cell arteritis

What does Transient retinal ischaemia increase risk of?

CRAO or BRAO, cerebrovascular accident (CVA)

What are the 2 types of Anterior ischaemic optic neuropathy (AION)?

Arteritic = inflammation of ciliary arteries or Non-arteritic = embolic /atherosclerotic/ thrombotic occlusion

AION Clinical Features

• Sudden painless profound loss of vision

• > 60 yrs

• Initially unilateral, May be preceded by amaurosis fugax

• Unilateral pale swolen optic disc

• APD

• Profound visual field loss

• Later optic atrophy

Key features of Non-arteritic AION?

• No other symptoms,

• Typically unilateral

• Some recovery possible

• PHM: vascular risk factors

• Untreatable

Key features of arteritic AION?

• Symptoms of Giant Cell (Temporal) Arteritis

• 95% bilateral if not treated

• Recovery rare

• Urgent treatment of underlying vasculitis is essential

What is an embolus?

an abnormal mass/particle that travels through the bloodstream and is capable of blocking a blood vessel distant from its point of origin

Origin of a Retinal artery emboli?

anywhere between heart and eye

Key features of Retinal artery emboli?

• May be transient - platelet embolus

• May be permanent and lodge in retinal arteriole, calcific / cholesterol embolus.

• Often difficult to see

What is Retinal Arterial Occlusion?

Abrupt cessation of blood flow through a retinal artery/arteriole sufficient to cause inner retinal ischaemia

central retinal artery is typically thrombotic or embolic

thrombotic

branched retinal artery is typically thrombotic or embolic

embolic

Retina Arterial Occlusion: Risk factors

• History of amaurosis fugax / retinal emboli

• Smoking

• Hypertension,

• Diabetes mellitus

• Hyperlipidaemia,

• Obesity

• Known cardiovascular disease

• Giant cell arteritis

RAO: Clinical Features?

Sudden profound painless loss of vision (6/240 or worse). Whole field (CRAO), Part field (BRAO), Central sparing if intact CilRA

Pupils: - APD (CRAO) - RAPD (BRAO)

Ophthalmoscopy:

• Inner retinal oedema

• 'Cherry Red Spot' for 4 - 6 weeks

• Sluggish / segmentation of arterial blood flow

• Retinal atrophy

• Disk pallor

• No recovery

Retinal arterial occlusion management?

Immediate

• try to re-establish circulation

• Rebreathing CO2 from bag

• Lower intraocular pressure

• Digital massage of globe

  Immediate referral to eye clinic (see that day)

• Lower intraocular pressure

• Anterior chamber paracentesis

• Look for underlying causes

Medical examination of heart and carotid arteries

Treat underlying disorders