Diabetic Retinopathy

Diabetic retinopathy is microvascular retinal disease and the leading cause of blindness in working age adults.

• After 20 years, over 90% of type 1 and over 60% of type 2 patients have some retinopathy.
• Stages: non proliferative (mild, moderate, severe), proliferative (neovascularisation), and diabetic macular oedema at any stage.
• Risk factors: duration, HbA1c, hypertension, dyslipidaemia, nephropathy, pregnancy, puberty.
• Complications: vitreous haemorrhage, tractional retinal detachment, neovascular glaucoma.

• Asymptomatic until advanced.
• Blurred vision from macular oedema, floaters or sudden loss from vitreous haemorrhage.
• Fundus: microaneurysms, dot blot haemorrhages, hard exudates, cotton wool spots, venous beading, IRMA, new vessels.

• Dilated fundus examination or retinal photography screening: at diagnosis in type 2, within 5 years in type 1 (from puberty), yearly thereafter, more often in pregnancy.
• OCT for macular thickness; fluorescein angiography for ischaemia and leakage.
• Severe NPDR by the 4-2-1 rule: haemorrhages in 4 quadrants, venous beading in 2, IRMA in 1.

• Systemic control: HbA1c about 7% (gradual lowering), blood pressure below 130/80 mmHg, statins, fenofibrate 145 mg daily slows progression.
• Diabetic macular oedema with central involvement: intravitreal anti VEGF (aflibercept 2 mg, ranibizumab 0.3 to 0.5 mg, bevacizumab 1.25 mg, faricimab 6 mg) monthly then extended; steroid implants (dexamethasone 0.7 mg) for poor responders.
• Proliferative disease: panretinal photocoagulation or anti VEGF; vitrectomy for non clearing haemorrhage or traction.
• Avoid rapid HbA1c drop in advanced retinopathy; semaglutide requires retinal monitoring.
• Referral thresholds: moderate NPDR or worse, any maculopathy, sudden vision loss.