- Diabetic retinopathy is thought to affect about 10% of patients with diabetes, but this rises to over 80% at 20 years after diagnosis of diabetes
The exact mechanism by which diabetes causes diabetic retinopathy is not well understood.
- Diabetic retinopathy is a type of microvascular complication of diabetes
- Development of diabetic retinopathy correlates to the time since diagnosis of diabetes – the longer the duration the higher the chance of diabetic retinopathy (80% have retinopathy after 20 years)
- Coexisting disease- especially hypertension
- Pregnancy– may accelerate retinopathy
- the development of microaneurysms which allow plasma leakage into the retina
- the development of ischaemic retina
- the development of AV shunts
Most patient are asymptomatic. Even in those with visual declines, the onset may be so insidious (slow and variable) that symptoms may not beneficed by the patient.
Haemorrhages may cause acute onset dark spots (‘floaters’). Severe haemorrhage may cause visual loss. Haemorrhages are painless.
- Assessment and diagnosis is very difficult without the use of a slit lamp and / or retinal photography.
- Microanueysms – weaknesses in the capillary walls leads to small aneurysms
- Hard exudates – collections of proteins that congregate on the retinal surface
- Cotton wool spots – shite ‘fluffy’ patches on the retina
- Haemorrhages – from repute of weakened capillaries. Typically larger in appearance than micoaneurysms
- Neovascularisation – new blood vessel formation – an attempt by the retina to heal
The main differential for diabetic retinopathy is macular degeneration – which can have some similar exudates on the retina. Late stage diabetic retinopathy however should be easy to differentiate due to the larger number of signs.
Non-proliferative retinopathy (background retinopathy)
- Dot and blot haemorrhages
- Cotton wool spots
- Hard exudates
The vision is usually NORMAL
- Macular oedema- gradual reduction in vision
- New vessel growth (neovascularisation)
- Retinal haemorrhage
- Vitreous haemorrhage- sudden loss of vision
- Optimal Management of DM
- Lifestyle factors – diet and exercise
- Aim or HbA1c <7%
- Optimal management of HTN
- Smoking cessation
- Encourage to go to screening
- Most common cause of blind registration in younger patients
- May be asymptomatic
- Annual Screening and prevention is key
- Laser and pan-retinal photocoagulation treatment is available in some circumstance