Diabetic retinopathy Flashcards
Diabetic retinopathy
Blood vessels in the retina are damaged by prolonged exposure to high blood sugar levels (hyperglycaemia) causing a progressive deterioration in the health of the retina
Pathophysiology of diabetic retinopathy
Hyperglycaemia leads to damage to the retinal small vessels and endothelial cells.
Increased vascular permeability:
- leakage from the blood vessels
- blot haemorrhages
- the formation of hard exudates
Damage to blood vessels:
- microaneurysms
- venous beading
- Intraretinal microvascular abnormalities (IMRA)
Damage to nerves:
- cotton wool spots
- Neovascularisation
Hard exudates
Yellow/white deposits of lipids in the retina
Microaneurysms
Weakness in the wall causes small bulges
Venous beading
Walls of the veins are no longer straight and parallel and look more like a string of beads or sausages
Cotton wool spots
Damage to nerve fibres in the retina causes fluffy white patches
Intraretinal microvascular abnormalities (IMRA)
Dilated and tortuous capillaries in the retina.
Can act as a shunt between the arterial and venous vessels in the retina
Neovascularisation
Growth factors are released in the retina causing the development of new blood vessels.
Classification of diabetic retinopathy
Non-proliferative (pre-proliferative)
- mild
- moderate
- severe
Proliferative
Proliferative diabetic retinopathy
New blood vessels developed - Neovascularisation at disc or within 1 DD of disc
Vitreous haemorrhage
Diabetic maculopathy
Separate to diabetic retinopathy
Causes:
- Macular oedema
- Ischaemic maculopathy
Mild non-proliferative Diabetic Retinopathy
Microaneurysms
Moderate non-proliferative Diabetic Retinopathy
Microaneurysms and at least 1 of:
- Blot haemorrhages
- Hard exudates
- Cotton wool spots
- Venous beading
Severe non-proliferative Diabetic Retinopathy (4-2-1 rule)
Blot haemorrhages plus microaneurysms in 4 quadrants
Venous beading in 2 quadrates
Intraretinal microvascular abnormality (IMRA) in any quadrant
Complications of diabetic retinopathy
Retinal detachment
Vitreous haemorrhage (bleeding in to the vitreous humour)
Rebeosis iridis
Optic neuropathy
Cataracts
Rebeosis iridis
New blood vessel formation in the iris
Management of proliferative diabetic retinopathy
Laser photocoagulation within 2 weeks - pan-retinal photocoagulation (PRP)
2 week follow up
Anti-VEGF medications such as ranibizumab and bevacizumab
Vitreoretinal surgery (keyhole surgery on the eye) may be required in severe disease
Risk factors for diabetic retinopathy
Long duration of diabetes Uncontrolled diabetes Hypertension Nephropathy Pregnancy Smoking Obesity
Why is there increased capillary leakage
Loss of pericytes
What causes occlusion of retinal arteries
Basement membrane thickening
Endothelial damage
RBC changes - rouleaux formation
Increased platelet aggregation
Rouleaux formation
Linking of RBCs into chains resembling stacks of coins
Background diabetic nephropathy
Microaneurysms
Blot haemorrhages
Hard exudate
Cotton wool spots
Management of background diabetic haemorrhage
Follow up every 9 months and observe
Pre proliferative diabetic nephropathy
Intraretinal microvascular aneurysms Venous looping Venous beading Cluster of large blot haemorrhages Multiple cotton wool spots
Management of pre proliferative diabetic nephropathy
Follow up every 4 months and observe
High risk proliferative diabetic retinopathy
Neovascularistaion (NVD) of more than 1/3rd of disc
or any with vitreous haemorrhage
Or neovascularisation elsewhere (NVE) of more than 1/2 disc area
Types of diabetic maculopathy
Focal Diffuse Ischaemia Mixed CSMO - clinically significant macular oedema Central involving
Focal diabetic maculopathy features
Well circumscribed areas of leakage with oedema
Full or partial ring of hard exudates surrounding a microaneursym region
Treatment of focal diabetic maculopathy features
Focal laser
Diffuse diabetic maculopathy features
Diffuse retinal thickness with cystoid oedema
Treatment of diffuse diabetic maculopathy
Grid laser
Investigations for diabetic maculopathy
Fundoscopy
OCT - optical coherence tomography
Fundus fluorescein angiography (FFA)
Features of ischaemic diabetic maculopathy
Reduced visual acuity
Normal clinical appearance
Macular ischaemia on fundus fluorescein angiography (FFA)
Management of ischaemic diabetic maculopathy
Observe
CSMO
Clinically significant macular oedema
CSMO features
Retinal thickening at or within 500 microns of the centre of the macula
Hard exudates at/within 500 microns of the centre of the macula - associated with adjacent retinal thickening
Retinal thickness of > 1 disc area, any part of which within 1DD of the centre of the macula
Mixed diabetic maculopathy features
Combination of diffuse and ischaemic diabetic maculopathy
Central involving diabetic maculopathy
Thickening involving the fovea centre > 400 micron
Treatment for central involving diabetic maculopathy
Anti VEGF injection IV iluvien (steroid) for persistent diabetic maculopathy
Complications of diabetes on eye
Retinopathy Iridopathy Unstable refraction Orbital infection Ocular ischaemic syndrome Recurrent stye or chalazion Accelerated senile cataract Neovascular glaucoma (NVG) Oculomotor nerve palsy Reduced corneal sensitivity Papillopathy - optic nerve pathology Tractional retinal detachment
Treatment of vitreous haemorrhage
Pan retinal photocoagulation same day or within 2 weeks
Persistent - vitrectomy + endolaser + anti VEGF
Treatment of Rubeosis
Urgent pan retinal photocoagulation
Anti VEGF
Intra ocular pressure reduction - cyclodiode
Ruberiosis
New blood vessel formation in iris
