What you need to know about diabetic retinopathy

Mr Maan Kasmiya is a consultant ophthalmologist surgeon at King’s College Hospital and honorary clinical lecturer at Imperial College London

Mr Maan Kasmiya Diabetic retinopathy (DR) is a complication of diabetes that affects the delicate part in the back of our eyes (retina), mainly due to uncontrolled blood sugar causing damage to the retinal vessels, which can lead to loss of vision if untreated. It’s also the leading cause of blindness worldwide in people aged 20 to 64 years.

DR affects up to 80% of those who’ve had diabetes for 20 years or more; however, 90% of new cases could be reduced with proper treatment and monitoring of the eyes.

THERE ARE TWO MAIN STAGES FOR DR

1. Non-proliferative diabetic retinopathy (NPDR) usually has no symptoms. The only way to detect NPDR is by fundus examination. Small bleeding, microaneurysms, accumulation of lipoproteins and changes in retinal vessels can be seen.

2. Proliferative diabetic retinopathy (PDR); abnormal new blood vessels (neovascularisation) form at the back of the eye as part of these can burst and bleed (vitreous haemorrhage, traction retinal detachment).

Macular oedema (swelling) is part of diabetic maculopathy, in which blood vessels leak their contents into the central vision and can cause blurry vision in early stages and can happen in any stage.

MECHANISM

Vascular endothelial growth factor (VEGF) is secreted by the ischemic (diseased) retina, causing retinal swelling/edema and new blood vessel formation.

DIAGNOSIS

Fluorescein angiography is used to determine the degree of ischemia in the retina; also OCT ocular coherence tomography can determine the size and location of swelling in macula area.

MANAGEMENT

This is done by systemic control and addressing the risk factors: blood sugar, hypertension, kidney problems, dyslipidaemia and smoking, uncontrolled glucose or bloodpressurelevelsareassociated with increased risk of DR (UKDPS, WESDR studies).

Treatment include: laser, injections inside the eye (IVT) and surgery in advanced cases.

Several studies ( DRCR, RIDE and RISE, DAVINCI and PLACID) indicated that anti-VEGF/ steroid injections are very effective in treating central macular edema MO, furthermore large studies, (DRCR protocol S and CLARITY) demonstrated that anti-VEGF injections was non-inferior to PRP laser (which is the current gold standard in the treatment of PDR).