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