Diabetic retinopathy is silent for years. That is the problem.

The retina does not complain

Diabetic retinopathy is damage to the small blood vessels of the retina caused by sustained high blood glucose. In its early stages it causes no symptoms at all. The vessels weaken, leak, and eventually bleed or grow fragile new branches. By the time a patient notices blurring, the retina has often already sustained damage that treatment can slow but not reverse.

Why Nigeria is behind on this

Screening rates for diabetic retinopathy in Nigeria are low, and the reasons are practical rather than clinical. Many patients see a physician for their diabetes but never see an eye specialist, because nobody referred them. Annual dilated fundus examination is standard of care internationally. It should be standard here too, and it frequently is not.

What the examination involves

Dilating drops widen the pupil so the retina can be photographed and examined directly. Optical coherence tomography gives a cross-sectional scan of the retinal layers, which catches macular oedema — swelling at the centre of vision — long before it shows up in a visual acuity test. The whole thing takes about half an hour, and your vision is blurry for a few hours afterwards.

Treatment, when it is needed

Focal laser photocoagulation seals leaking vessels. Panretinal photocoagulation treats the fragile new vessels of proliferative disease. Intravitreal injections deliver anti-VEGF drugs directly into the eye to reduce macular swelling. All of these slow progression. None of them restore vision that has already been lost, which is the reason screening beats treatment.

How often

For most patients with diabetes and no retinopathy, annually. If retinopathy is present, the interval shortens to every three to six months depending on severity. Pregnancy accelerates diabetic eye disease, so pregnant patients need assessment early and often.

What you can control

Blood glucose, blood pressure and lipids. Tight control reduces the risk of retinopathy progression substantially. It does not eliminate the need for screening, but it changes what screening finds.