Summary

Diabetic Retinopathy (DR) is a microvascular complication of diabetes affecting the retina. It is the leading cause of preventable blindness in working-age adults in developed countries. DR progresses through stages: Non-Proliferative DR (NPDR) – subdivided into Background (R1), Pre-proliferative (R2) – and Proliferative DR (PDR, R3), characterised by neovascularisation (new fragile vessel growth), which carries high risk of vitreous haemorrhage and tractional retinal detachment. Diabetic Maculopathy (M1) – oedema or exudates affecting the macula – can occur at any stage and is the main cause of moderate vision loss. Risk factors include duration of diabetes, poor glycaemic control, and hypertension. Management involves screening (annual retinal photography), systemic control (HbA1c, BP, Lipids), Anti-VEGF injections for maculopathy and some PDR, and Pan-Retinal Photocoagulation (PRP) laser for proliferative disease.

Key Facts

• Epidemiology: ~35% of diabetics have some DR. ~7% have sight-threatening DR.
• Classification: Background (R1), Pre-Proliferative (R2), Proliferative (R3), Maculopathy (M1).
• Background (R1): Microaneurysms, Dot/Blot Haemorrhages, Hard Exudates.
• Pre-Proliferative (R2): Cotton Wool Spots (Ischaemia), Venous Beading, IRMA.
• Proliferative (R3): Neovascularisation (NVD/NVE). Risk of Vitreous Haemorrhage.
• Maculopathy (M1): Oedema/Exudates near Fovea. Main cause of moderate vision loss.
• Treatment: Optimise Glycaemic/BP control. Anti-VEGF. PRP Laser. Vitrectomy.

Clinical Pearls

"No Symptoms Until Late": Early DR is asymptomatic. Screening saves sight.

"Cotton Wool Spots = Retinal Ischaemia = Pre-Proliferative": This is a warning sign that proliferative disease may follow.

"New Vessels Bleed": Neovascularisation (PDR) is fragile and bleeds into the vitreous, causing sudden vision loss.

"Maculopathy is the Central Vision Thief": Oedema at the macula affects reading/driving vision.

Why This Matters Clinically

Diabetic retinopathy is preventable with screening and early treatment. PRP laser for PDR prevents severe visual loss. Anti-VEGF has revolutionised maculopathy treatment.

Non-Proliferative Diabetic Retinopathy (NPDR)

R0: No Retinopathy

• Normal fundus.

R1: Background Retinopathy

R1 = Low risk. Annual screening.

R2: Pre-Proliferative Retinopathy

R2 = High risk of progression. Refer to Ophthalmology. Closer monitoring.

Proliferative Diabetic Retinopathy (PDR)

R3: Proliferative Retinopathy

R3 = Sight-Threatening. Urgent referral. May need PRP or Anti-VEGF.

Maculopathy (M1)

M1 = Sight-Threatening. Referral. Anti-VEGF or Laser.

Summary Table

Key Guidelines

Key Trials

Scenario 1:

• Stem: A diabetic patient's screening photo shows microaneurysms and hard exudates, but no cotton wool spots or new vessels. What is the grading?
• Answer: R1 (Background Retinopathy). Continue annual screening. Optimise systemic control.

Scenario 2:

• Stem: A diabetic patient has cotton wool spots and venous beading. What is the significance?
• Answer: R2 (Pre-Proliferative Retinopathy). Signs of retinal ischaemia. High risk of progression to proliferative disease. Refer to Ophthalmology.

Scenario 3:

• Stem: What is the treatment for Proliferative Diabetic Retinopathy?
• Answer: Pan-Retinal Photocoagulation (PRP) Laser. Anti-VEGF as adjunct.

What is Diabetic Retinopathy?

Diabetic Retinopathy is damage to the back of your eye (the retina) caused by diabetes. High blood sugar damages the tiny blood vessels, which can leak or become blocked.

Why is screening important?

Early changes have no symptoms. Annual eye screening can detect problems before you notice, allowing treatment to prevent vision loss.

How is it treated?

• Good Blood Sugar and Blood Pressure Control: The most important thing.
• Laser Treatment: Seals leaking vessels or destroys abnormal ones.
• Eye Injections (Anti-VEGF): Injections into the eye to reduce swelling and stop new vessel growth.
• Surgery (Vitrectomy): If there is bleeding or retinal detachment.

Key Counselling Points

1. Attend Screening: "Annual eye checks can save your sight."
2. Control Blood Sugar and BP: "This is the best way to protect your eyes."
3. Report Vision Changes: "If your vision suddenly changes, seek urgent help."

• PRP Laser (1970s): Diabetic Retinopathy Study (DRS) proved PRP reduces severe vision loss.
• ETDRS (1985): Established macular laser for clinically significant macular oedema.
• Anti-VEGF Era (2010s): Revolutionised treatment of DME. Superior to laser for central-involving DME.
• NHS DESP (2003): National screening programme in England – Significantly reduced diabetic blindness.