Makindo Medical Notes | Diabetes: Eye Disease

👁️ Diabetic retinopathy is largely preventable: tight glycaemic control, BP and lipids slow microvascular damage; timely laser/anti-VEGF preserves sight. In the UK, routine annual screening from age 12 (NHS DES) catches asymptomatic disease early.

📖 About

~50% of T1D affected within 10–15 years; ~50% of T2D within 15 years. Most changes are mild if detected early.
Risk rises with diabetes duration, hyperglycaemia (HbA1c), hypertension, dyslipidaemia, nephropathy, pregnancy, and smoking.

🧠 Pathophysiology (why VEGF rises)

Chronic hyperglycaemia → pericyte loss, basement-membrane thickening, capillary dropout → retinal ischaemia.
Ischaemia ↑VEGF → ↑permeability (macular oedema) and fragile neovascularisation (proliferative disease).

🩺 Screening (UK focus)

Annual mydriatic digital photography (NHS DES). Symptomless until late stages—screening is crucial.
Pregnancy (pre-existing diabetes): retinal assessment at booking (1st trimester) and again at 28 weeks; if retinopathy at booking, add a review at 16–20 weeks.

🔎 Classification → what it means

Background (R1): microaneurysms, dot/blot haemorrhages, hard exudates. Usually asymptomatic.
Pre-proliferative (R2): venous beading, multiple blot haemorrhages, IRMA/cotton-wool spots = significant ischaemia.
Proliferative (R3): new vessels at disc/elsewhere ± pre-retinal/vitreous haemorrhage → high risk of tractional detachment.
Maculopathy (M1): macular oedema/exudates within 1 disc diameter of fovea or reduced acuity from oedema.

🚦Referral urgency (practical)

🔴 R3 or M1 with reduced vision: urgent same-week ophthalmology (often same-day if vitreous haemorrhage/sudden floaters or vision drop).
🟠 R2: prompt routine referral (weeks).
🟢 R1: continue annual screening; optimise risk factors.

🧰 Management

Risk factor optimisation: individualised HbA1c target, strict BP control, statin/ACEi as indicated, smoking cessation.
Macular oedema (centre-involving): intravitreal anti-VEGF (e.g., aflibercept/ranibizumab); steroids in selected cases.
Proliferative retinopathy: pan-retinal photocoagulation (PRP); anti-VEGF as adjunct/bridge.
Advanced disease: vitrectomy for non-clearing vitreous haemorrhage or tractional retinal detachment.

⚠️ Red flags (act now)

Sudden floaters, curtain over vision, or acute vision drop → possible vitreous haemorrhage/retinal detachment → same-day eye assessment.
Pregnancy with progressive retinopathy → expedite ophthalmology review.

📚 Teaching diagram placeholders

Non-proliferative vs proliferative changes

🧑‍⚕️ Case vignette

A 58-year-old with T2D (12 yrs), HbA1c 74 mmol/mol, BP 154/92, reports mild central blur. Screening photo shows hard exudates within 1DD of the fovea and thickening on OCT. ✅ M1 maculopathy → refer urgently for anti-VEGF; tighten BP and glucose; start/optimise statin and ACEi.

💡 Mentor tip

If you remember just three things for viva: duration drives risk, VEGF links ischaemia to oedema/neovascularisation, and R3/M1 need urgent eyes-on. Everything else is risk-factor medicine.

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Diabetes: Eye Disease