Diabetic retinopathy !
Diabetic retinopathy is damage to the small blood vessels of the retina from long-standing diabetes; it is a leading cause of preventable blindness.
Updated 2026-10-30
Structures involved
Tap one to see what it is and open it in 3D.
In histology
In the clinical exam
In physiology
Why it happens
What it is
Damage to the small blood vessels of the retina caused by long-standing diabetes. It ranges from leaky, blocked capillaries to new fragile vessels and macular swelling, and is a leading cause of preventable blindness in working-age adults.
Who gets it
Its frequency rises with the duration of diabetes and poor control of blood sugar and blood pressure. A 2024 meta-analysis for Latin America and the Caribbean estimated retinopathy in 37.3% of people with type 2 and 40.6% with type 1 diabetes, with very uncertain evidence. Screening coverage in primary care remains a challenge.
Causes
- Chronic hyperglycaemia in type 1 or type 2 diabetes
- Microvascular damage: pericyte loss, basement membrane thickening and capillary closure
Risk factors
- Long duration of diabetes
- Poor glycaemic control
- Arterial hypertension
- Dyslipidaemia
- Diabetic kidney disease
- Pregnancy (can speed progression)
Pathophysiology
High glucose damages capillary pericytes and endothelium, causing microaneurysms, leakage and closure of capillaries. The ischaemic retina releases vascular endothelial growth factor (VEGF), which drives fragile new vessels on the retina, disc and iris. Leakage into the macula causes macular oedema, the commonest cause of vision loss.
Classification
- Non-proliferative: mild, moderate or severe (microaneurysms, haemorrhages, hard exudates, cotton-wool spots, venous beading)
- Proliferative: new vessels on the disc or elsewhere, vitreous haemorrhage, traction
- Diabetic macular oedema, centre-involving or not; can occur at any stage
Symptoms and signs
- Often no symptoms until advanced
- Gradually blurred central vision (macular oedema)
- Sudden floaters or loss of vision from vitreous haemorrhage
- Distorted vision
- Fundus: microaneurysms, dot-and-blot haemorrhages, hard exudates, cotton-wool spots, new vessels
Diagnosis
- Clinical
- Dilated fundus examination by an eye professional, or retinal photographs read by trained graders or validated automated systems. Screening starts soon after type 2 diabetes is diagnosed and some years after type 1 onset; intervals vary.
- Tests
- HbA1c, blood pressure, lipids and kidney function guide overall risk. Fluorescein angiography shows leakage, closed capillaries and new vessels.
- Imaging
- Optical coherence tomography (OCT) measures macular thickness and guides treatment of oedema. Ocular ultrasound when vitreous haemorrhage hides the retina.
Differential diagnosis
- Hypertensive retinopathy
- Retinal vein occlusion
- Radiation retinopathy
- Ocular ischaemic syndrome (carotid disease)
- Sickle cell retinopathy
Goal of treatment
Prevent progression and vision loss by controlling the systemic disease, treating macular oedema and closing or regressing new vessels before they bleed or pull the retina.
Treatment
- Lifestyle
- Good control of blood glucose, blood pressure and lipids, plus not smoking; this slows the onset and progression of retinopathy.
- Medical
- Intravitreal anti-VEGF drugs: first-line for centre-involving macular oedema and also used in proliferative disease. Intravitreal corticosteroids are an alternative.
- Procedure
- Panretinal laser photocoagulation for proliferative retinopathy: treating the ischaemic periphery reduces VEGF and makes new vessels regress. Focal laser for some macular oedema.
- Surgical
- Vitrectomy for non-clearing vitreous haemorrhage or tractional retinal detachment.
- Follow-up
- Regular screening with retinal photographs or examination, more often as disease advances and during pregnancy.
Complications
- Diabetic macular oedema
- Vitreous haemorrhage
- Tractional retinal detachment
- Neovascular glaucoma
- Permanent blindness
Prognosis
Early detection and timely treatment prevent most severe vision loss. Untreated proliferative disease and centre-involving macular oedema carry a high risk of blindness.
Prevention
- Regular retinal screening for everyone with diabetes
- Control of glucose, blood pressure and lipids
- Eye examination before and during pregnancy in women with pre-existing diabetes
Test yourself
Think of the answer, then tap the question to see it.
What is the commonest cause of vision loss in diabetic retinopathy?
Diabetic macular oedema, from leakage of fluid into the central retina.
What finding defines proliferative diabetic retinopathy?
Neovascularisation: new vessels on the optic disc or elsewhere on the retina, often with vitreous haemorrhage.
Which growth factor drives new vessel formation and macular oedema?
Vascular endothelial growth factor (VEGF), released by the ischaemic retina.
What is the standard laser treatment for proliferative retinopathy?
Panretinal photocoagulation of the ischaemic peripheral retina.
Which test measures macular thickness and guides treatment of oedema?
Optical coherence tomography (OCT).
Related conditions
- Type 2 diabetes mellitus
- Type 1 diabetes mellitus
- Arterial hypertension
- Retinal detachment
- Cataract
- Open-angle glaucoma
- Age-related macular degeneration
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Diabetic Retinopathy (StatPearls (NCBI Bookshelf), 2023); Prevalence and incidence of diabetic retinopathy in patients with diabetes of Latin America and the Caribbean: A systematic review and meta-analysis (PloS one, 2024) · adapted, CC BY 4.0.
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.
