Diabetic retinopathy is the most common cause of blindness in adults aged 30–65.
It progresses from non-proliferative to proliferative stages, with neovascularisation and risk of vitreous haemorrhage.
Annual screening is essential in all diabetic patients unless very low risk.
🧬 Pathophysiology
Chronic hyperglycaemia causes microvascular damage to the retinal capillaries
Leads to capillary leakage, ischaemia, and neovascularisation
Progresses from non-proliferative to proliferative diabetic retinopathy (PDR)
🧪 Screening
Annual retinal screening for all patients with T1DM and T2DM
For T2DM with low risk (no retinopathy on last 2 screenings), screening may be offered biannually
👀 Staging of Diabetic Retinopathy
Stage 1: Mild NPDR
Microaneurysms only
Stage 2: Moderate NPDR
Blot haemorrhages
Hard exudates
Cotton wool spots
Venous looping
Stage 3: Severe NPDR
Blot haemorrhages in all 4 quadrants
Venous beading in ≥ 2 quadrants
IRMA (intraretinal microvascular abnormality) in ≥ 1 quadrant
Figure 156: Diabetic retinopathy. A fundus image showing several signs of diabetic retinopathy: hard exudates (scattered yellowish dots), microaneurysms (bulges off some blood vessels), and small hemorrhages (blurry red dots).Shaofeng Hao, Changyan Liu, Na Li, Yanrong Wu, Dongdong Li, Qingyue Gao, Ziyou Yuan, Guanyan Li, Huilin Li, Jianzhou Yang, and Shengfu Fan., Fundus - diabetic retinopathy, CC BY 4.0
Proliferative Diabetic Retinopathy (PDR)
Neovascularisation present
New vessels may bleed → vitreous haemorrhage → sudden visual loss
50% of patients with PDR are registered blind within 5 years
Figure 157: Diabetic retinopathy- proliferative.
👁️ Differentiating Hypertensive Retinopathy
Arteriolar narrowing
Arteriovenous (AV) nipping
Cotton wool spots, flame-shaped haemorrhages
Papilloedema (in malignant hypertension)
Figure 160: Hypertensive retinopathy- AV nicking and vascular tortuosity. Frank Wood, Hypertensiveretinopathy, CC BY 3.0
