Retinal Vascular Disease Lectures Flashcards
What are the risk factors for diabetic retinopathy?
Diabetes duration Hyperlipidaemia Poor glycaemic control Hypertension Smoking Ethnicity (black/Hispanic)
What was the landmark diabetic retinopathy trial?
UKPDS (Younis et al, 2002)
What are the common ophthalmic complications of diabetes?
Retinopathy
Iridopathy
Unstable refraction
What is the disease process in diabetic retinopathy (DR) that compromises retinal perfusion?
Microangiopathy
What components make up retinal capillaries?
Endothelial cells (blood-retinal barrier)
Basement membrane
Pericytes
What are the effects of hyperglycaemia on retinal capillaries?
Endothelial cell/pericyte apoptosis
More porous basement membrane
Reduced retinal perfusion
VEGF breaks down blood-retinal barrier
What are the two forms of capillary damage in diabetic retinopathy?
Exudative (macular oedema)
Ischaemic (neovascularisation)
What signs are seen in exudative diabetic retinopathy?
‘Dot’ and ‘blot’ haemorrhages
Intraretinal oedema
Hard exudates
Which investigations may be used to identify fluid in retinal layers?
Fundoscopy
OCT
Which investigation may be used to identify retinal vessel leakage?
Fluorescein angiography (FA)
What is a retinal micro-aneurysm?
Asymmetrical dilatation of weakened capillary wall after pericyte loss
What is the classical appearance of macular oedema on fluorescein angiography?
Petal-shaped
What factors lead to capillary occlusions secondary to intravascular coagulation?
More platelet stickiness
More leucocyte adhesion
Less endothelial function
Altered haemodynamics
What is the macular consequence of ischaemic diabetic retinopathy
Enlargement of the foveal avascular zone (no treatment available)
What fundoscopy signs are seen in severe retinal ischaemia?
Extensive haemorrhages
Cotton wool spots
Engorged retinal veins
IRMA
Cotton wool spots are found in which retinal layer? Which imaging form identifies them well?
Nerve fibre layer Fluorescein angiography (FA)
Proliferative diabetic retinopathy is caused by which angiogenic factor and which cells produce this protein?
VEGF
Retinal endothelial cells
What are the stages of angiogenesis?
Invasion Mitosis Canalisation Loop formation Vascular arcade formation
Which proliferative diabetic retinopathy complications are treatable?
Macular oedema
Neovascularisation
What examinations and investigations are carried out for DR patients?
Visual acuity/fields
Colour/red-free fundus imaging
Fluorescein angiography
OCT (especially for macular oedema)
What are the diabetic retinopathy classification stages?
R0: No retinopathy
R1: Few I/R haemorrhages, hard exudates, cotton wool spots
R2: Many I/R haemorrhages, venous beading/loops, IRMA
R3: Neovascularisation, pre-retinal haemorrhage, fibrosis, tractional retinal detachment
How is diabetic maculopathy classified?
M0: No disease
M1a: Exudate <1 disc diameter of foveal centre, >half disc area (<1DD: M1b)
M1c: Microaneurysm, haemorrhage <1DD of foveal centre if best VA <6/12
How do inflammatory retinal disorders commonly present?
Vision loss, floaters
Anterior uveitis
Vitreous opacities
White patches/retinal vessels
What neurodegenerative condition is characterised by blunted venules, an elongated foveal tip on OCT and a pale fovea?
Macular telangiectasia type 2
What are the main systemic diseases with ocular manifestations?
Diabetes
Hypertension
Thyroid disease
Rheumatoid arthritis (Sjorgren’s syndrome)
What condition is characterised by iris Lisch nodules and café-au-lait spots?
Neurofibromatosis type I
What inflammatory condition requires urgent referral if it presents with ocular manifestations?
Rheumatoid arthritis
How does rheumatoid arthritis present in the eyes?
Red eyes
Necrotising keratitis
Sjorgren’s syndrome/dry eyes
Which ophthalmic conditions of systemic origin commonly present in hospital?
Peripheral ulcerative keratitis
Uveitis
Retinitis
Ophthalmic neuritis
What are the ophthalmic consequences of diabetes?
Cataracts (<40’s)
Risk of retinal vessel occlusion
Cranial nerves III, IV, VI palsies
Diabetic retinopathy
What is the classification of diabetic retinopathy?
Background
Pre-proliferative
Proliferative
What are the features of background diabetic retinopathy?
Microaneurysms
‘Dot’ and ‘blot’ haemorrhages
What are the features of pre-proliferative diabetic retinopathy?
Haemorrhages and microaneurysms
Cotton wool spots
IRMA
Venous abnormalities (beading, loops)
How is moderate and severe pre-proliferative DR classified?
Moderate: 1 quadrant venous beading, IRMA
Severe: 4:2:1 quadrants, 4 with haemorrhage or 2 with venous beading or 1 with IRMA
What are the features of proliferative diabetic retinopathy?
Neovascularisation (Disk: NVD, elsewhere: NVE)
Pre-retinal/vitreous haemorrhages (worse)
Retinal fibrosis
Tractional retinal detachment (worst)
How is proliferative diabetic retinopathy treated?
Anti-VEGF agents
Argon laser therapy
What are the features of diabetic maculopathy?
Early vision loss
Macular HMA’s, exudates, oedema
What are the differences on fundoscopy between exudative and ischaemic diabetic retinopathy?
Exudative DR causes maculopathy but ischaemic DR usually does not
What is the pathogenesis of diabetic retinopathy prior to microvascular leakage?
Basement membrane thickening Endothelial/pericyte damage Capillary venule outpouching RBC changes, higher platelet viscosity Hypoxia retina releases VEGF: angiogenesis
What anterior segment sign is seen in proliferative diabetic retinopathy?
Rubeosis iridis
What is the earliest clinically detectable change seen in diabetic retinopathy?
Microaneurysms
What angiogenic factors are release following retinal hypoxia?
Growth factors (IGF-1, EGF, etc.) VEGF (protein kinase-C activation)
How can diabetic retinopathy progression be reduced?
Less dietary sugar, fat, cholesterol
Statins, laser treatment
How is diabetic maculopathy treated?
Diabetes/BP control
Statins, anti-VEGF, laser therapy
Intravitreal steroids (dexamethasone, fluocinolone)
How is ischaemic diabetic retinopathy treated?
Diabetes/BP control alone
What is the gold standard treatment for diabetic eye disease?
Panretinal photocoagulation
When is VR surgery indicated in diabetic eye disease?
Rubeosis iridis, haemorrhages (if sub-hyaloid sleep elevated)
Retinal detachment
Vitreomacular traction (posterior hyaloid, epiretinal membranes)
What types of retinal detachment are there?
Tractional
Rhegmatogenous
Combined
How is refractory DMO treated?
Iluvien (DEX implant)
PPV +/- ILM peel
What are the aims of diabetic vitrectomy?
Relieving antero-posterior/tangential traction, less bleeding
Improves laser efficiency
What are the consequences of microvascular leakage in proliferative diabetic retinopathy?
Microaneurysms
Retinal oedema
Hard exudates
What features are seen in hypertensive retinopathy?
AV nipping, papilloedema
B/CRVO (biggest cause)
What features are seen in thyroid eye disease?
Dry, painful eyes Conjunctival injection Lid retraction/oedema Proptosis, diplopia Optic nerve compression
How is thyroid eye disease managed?
Symptomatic treatment
Immunosuppression, surgery
Emergency: Orbital decompression
What are the signs of 3rd cranial nerve palsy?
Ptosis
Inferior, temporal unreactive pupil
What are the causes of a 3rd cranial nerve palsy?
Vasculopathy (DM, hypertension)
Aneurysm (refer to surgery!)
What is the blood supply of the retina
Internal carotid artery -> Ophthalmic artery -> Central retinal artery
Outer third supplied by the choroid
Inner two-third’s supplied by the central retinal artery
What is the blood supply of the choroid?
Short and long posterior ciliary arteries
What is are the physical differences between retinal arteries and retinal veins?
Retinal veins are larger and redder than retinal arteries
Which retinal layers contain the superficial, intermediate and deep plexus?
Superficial: Inner plexiform layer
Intermediate: Inner nuclear layer
Deep: Outer plexiform layer
What 500μm region of the macula is responsible for the highest visual resolution?
Foveal avascular zone (FAV)
What is the blood supply of the retinal photoreceptors?
Choroid
What cells make up the inner and outer blood-retinal barriers?
Inner: Endothelial cells
Outer: RPE cells
How does retinal vein occlusion present?
Sudden painless visual loss
RAPD if ischaemic
What investigations do ophthalmologists order if RVO is suspected?
BP
OCT
Fluorescein angiography
What investigations do GP’s order if RVO is suspected?
FBC, ESR, thrombophilia screen, CRP, rheumatoid factor U&E’s, serum ACE Blood glucose, cholesterol ECG, X-ray Thyroid function test
What fundoscopy signs are seen in RVO?
Flame and 'blot' haemorrhages Intraretinal oedema Cotton wool spots Engorged retinal veins Collateral retinal vessels
What are the treatable complications of RVO?
Macular oedema
Neovascularisation (ischaemia)
What OCT signs are seen in RVO?
Exudative fluid-filled subretinal/outer nuclear layer spaces
Hyperreflective track lines
Who pioneered vitreo-retinal surgery?
Dr Robert Machemer
Professor McLeod
What factors affect the need for vitreo-retinal surgery?
Haemorrhage time Status of fellow eye Retinal detachment Vitreomacular traction Prior laser Premacular/intragel
What are the indications for vitreo-retinal surgery?
Rubeosis iridis, haemorrhages
Retinal detachment
Vitreomacular traction
What developments have improved vitreo-retinal surgery?
23-27G needles
Bimanual, wide-angle illumination
Oculoplasmin
What are the indications for surgery in RVO?
Vitreous haemorrhages
Epiretinal membranes
How is vitreous haemorrhage graded?
0: None
1: Mild, visible retina
2: Moderate, no visible retina, red reflex present
3: Severe, retina/red reflex not visible
Which surgical interventions are used to treat RVO?
Adventitial sheathotomy
Chorioretinal anastamoses
Radial neurotomy
What are the main causes of CRVO?
Central retinal vein thrombosis
Central retinal artery atherosclerosis
What are the risk factors for CRVO?
Hypertension Diabetes Hyperlipidaemia Obesity Smoking Glaucoma Blood hyperviscosity syndromes
Why is anti-VEGF given pre-op? When can it be given? Any risks?
Better manipulation, less vitreous bleeding
Beneficial in rubeosis iridis
7 days up to 24 hours before surgery
Fibrosis risk
What is the pathogenesis in central retinal vein occlusion?
Narrowed vein, flow turbulence, partial thrombosis
Less venous outflow, high vein pressure
Oedema, haemorrhage, ischaemia
VEGF, endothelial damage, occlusion, glaucoma
What are the 3 classes of retinal vein occlusion?
Ischaemic
Non-ischaemic
Indeterminate
What classification factors suggest ischaemic CRVO?
> 10 disc diameters non-perfusion on FFA
RAPD (>1.2 logMAR units)
(NVI/NVA, <20/200 VA, perimetry, electroretinogram)
What classification factors suggest non-ischaemic CRVO?
<10 disc diameters non-perfusion on FFA