About This Page
This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Leading cause of blindness in working-age adults in the UK — screening catches it early
- NHS Diabetic Eye Screening Programme: annual digital retinal photography for all diabetic patients aged 12+
- Grading: background (R1) → pre-proliferative (R2) → proliferative (R3) → maculopathy (M1)
- Proliferative DR: neovascularisation — treat with panretinal photocoagulation (PRP) or anti-VEGF
- Diabetic macular oedema (DMO): centre-involving → intravitreal anti-VEGF (NICE NG242, 2024)
Overview
Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus caused by chronic hyperglycaemia-induced damage to the retinal vasculature. Non-proliferative DR is characterised by microaneurysms, haemorrhages, hard exudates, and cotton wool spots. Proliferative DR occurs when retinal ischaemia drives VEGF-mediated neovascularisation — new fragile vessels prone to haemorrhage and tractional retinal detachment. Diabetic macular oedema (DMO) can occur at any stage and is the commonest cause of visual loss in diabetic eye disease.
Epidemiology
Approximately 4.7 million people in the UK have diabetes, and around one-third will develop some degree of retinopathy. DR is the leading cause of blindness in people of working age (16–64). After 20 years of diabetes, nearly all type 1 and over 60% of type 2 patients have some retinopathy. Key risk factors include duration of diabetes, poor glycaemic control (HbA1c), hypertension, dyslipidaemia, nephropathy, pregnancy, and rapid improvement of glycaemic control (paradoxical early worsening).
Clinical Features
Symptoms
Often ASYMPTOMATIC until advanced — hence the importance of screening
Gradual blurring of vision (macular oedema)
Sudden painless floaters or visual loss (vitreous haemorrhage from proliferative DR)
Sudden visual loss with a "curtain" or shadow (tractional retinal detachment)
Distortion of central vision (macular oedema)
Signs
Microaneurysms — earliest visible sign, appear as tiny red dots
Dot and blot haemorrhages (intraretinal)
Hard exudates — yellow lipid deposits, often in a circinate pattern
Cotton wool spots — retinal nerve fibre layer infarcts indicating ischaemia
Venous beading, looping, and IRMA — pre-proliferative signs
Neovascularisation on the disc (NVD) or elsewhere (NVE) — hallmark of proliferative DR
Vitreous or pre-retinal haemorrhage
Macular oedema — thickening visible on OCT
Investigations
First-line
NHS Diabetic Eye ScreeningAnnual screening for all diabetic patients aged 12+ using two-field digital photography through dilated pupils
Visual acuityLogMAR or Snellen at each assessment
Slit-lamp biomicroscopy with fundoscopyDetailed assessment in hospital eye service for referrals
Second-line
OCTEssential for diagnosing and monitoring diabetic macular oedema — measures central retinal thickness
HbA1c, blood pressure, lipid profileAssess systemic risk factors
Specialist
Fluorescein angiographyIdentifies areas of capillary non-perfusion, neovascularisation, and leakage
Ultra-widefield imagingDetects peripheral ischaemia and neovascularisation missed by standard photography
1
Systemic optimisation (all stages)
- Optimise glycaemic control — BUT avoid excessively rapid reduction (risk of early worsening)
- Blood pressure control (<140/80 mmHg; <130/80 if target organ damage)
- Consider fenofibrate for type 2 diabetes with non-proliferative DR (NICE NG242)
- Annual diabetic eye screening attendance
2
Non-proliferative DR (R1/R2)
- Background DR (R1): annual screening, systemic optimisation
- Pre-proliferative DR (R2): refer to hospital eye service, monitor closely (3–6 monthly)
3
Proliferative DR (R3)
- Panretinal photocoagulation (PRP) — standard of care
- Anti-VEGF injection (ranibizumab) — alternative or adjunct to PRP
- Vitrectomy for non-clearing vitreous haemorrhage (>3 months) or tractional retinal detachment
4
Diabetic macular oedema (DMO)
- Centre-involving DMO with VA loss + CRT ≥400 µm: offer intravitreal anti-VEGF (NICE NG242)
- Centre-involving DMO with CRT <400 µm: consider anti-VEGF or macular laser
- Non-centre-involving DMO: focal/grid macular laser photocoagulation
- If suboptimal response at 12 months: consider intravitreal steroid implant (dexamethasone)
Complications
- Vitreous haemorrhage: From rupture of fragile new vessels
- Tractional retinal detachment: Fibrovascular proliferation contracts, pulling the retina off
- Neovascular glaucoma: Rubeosis iridis blocking drainage angle
- Permanent macular damage: Chronic oedema leads to photoreceptor loss
UKMLA Exam Tips
- 1Microaneurysms are the EARLIEST sign of diabetic retinopathy — tiny red dots on fundoscopy
- 2Cotton wool spots = nerve fibre layer infarcts = retinal ISCHAEMIA — a pre-proliferative warning sign
- 3NVD/NVE = proliferative disease = PRP is the mainstay
- 4Anti-VEGF is first-line for centre-involving DMO with significant macular thickening (≥400 µm)
- 5Rapid HbA1c reduction can paradoxically WORSEN retinopathy in the short term
- 6NHS screening uses R0/R1/R2/R3/M1 grading — know this classification system
- 7NVD carries higher risk of vitreous haemorrhage than NVE
practicetest your knowledge on diabetic retinopathyApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — ophthalmology and beyond.
open q-bank