What Is Diabetic Retinopathy?

Diabetic retinopathy is an eye condition caused by damage to the retina's blood vessels from prolonged high blood sugar. It's one of the leading causes of vision loss in people with diabetes and usually affects both eyes. Symptoms may not appear at first, so anyone diagnosed with diabetes should have regular retina examinations. Ophthalmologists group it into an early (non-proliferative) stage, where the vessels haven't yet bled or leaked, and an advanced (proliferative) stage, where abnormal new vessels form — the stage shapes how often you're monitored and what treatment is needed. Among retinal diseases, it stands apart for being tied directly to diabetes and its duration.

Diabetic retinopathy can develop in both type 1 and type 2 diabetes, and the risk rises the longer someone has had diabetes. Early-stage disease may not need treatment, but advanced stages can require intravitreal injections or laser treatment. Unnoticed, untreated cases risk permanent vision loss, and an ophthalmologist manages the condition. Review frequency depends on the stage: an annual eye examination may be enough early on, while advanced disease may need checks every few months. Keeping blood sugar, blood pressure and cholesterol under control also affects how the retinal findings progress. Because the condition can progress faster during pregnancy, women with diabetes planning to conceive should also have an eye examination.

Over the years, diabetes can damage the body's small blood vessels, and the retina, which depends heavily on them, is directly affected. High blood sugar weakens the retinal vessel walls and causes leakage; in later stages, vessels can become blocked or abnormal new ones can form. Because these new vessels are fragile, they can bleed and damage the retinal tissue. Another consequence is fluid accumulating in the macula — the part of the retina responsible for sharp central vision — known as diabetic macular oedema, a major cause of blurred vision. Where blockage progresses, the tissue no longer gets enough blood and oxygen, so the eye tries to compensate by growing new vessels that are far less sturdy than healthy ones.

In the early stages, most patients have no noticeable complaints, which is why diabetic retinopathy can progress silently. As it advances, blurred vision, dark patches or spots in the visual field, floaters, and faded colours can appear, and advanced stages may bring sudden, marked vision loss. Some patients also notice poorer night vision or reduced contrast. Once macular oedema develops, reading and recognising faces can become noticeably harder. Severity varies widely between patients.

The underlying cause is prolonged, poorly controlled high blood sugar. Risk increases the longer someone has had diabetes; high blood pressure, high cholesterol, pregnancy and smoking are additional factors affecting its course. Keeping blood sugar under regular control helps slow its development. Some factors — blood sugar, blood pressure, cholesterol and smoking — are within a person's control, while others, such as diabetes duration, cannot be changed.

As soon as diabetes is diagnosed, a retina examination is recommended even without complaints. If blurred vision, floaters, or dark patches in the visual field appear, see an ophthalmologist without delay — diabetic retinopathy can progress silently, so regular checks matter more than waiting for symptoms. This first assessment is usually a fundus examination: the pupil is dilated with drops so the whole retina can be examined in detail. In type 1 diabetes, the first fundus examination is generally recommended within a few years of diagnosis; in type 2 diabetes, at diagnosis itself. Sudden vision loss or a curtain across your vision need urgent assessment.

Diabetic retinopathy is diagnosed with a detailed retina examination. Visual acuity is measured and your eye history reviewed first; the pupil is then dilated and the retina examined directly. When needed, OCT imaging assesses thinning, thickening or fluid build-up in the retinal layers. If mapping vessel leakage or blockage is required, fluorescein angiography may also be used, as part of a comprehensive retina examination.

Treatment may not be needed in the early stages, when regular follow-up and blood sugar control take priority. As fluid build-up or abnormal vessel growth develops, treatment becomes necessary; untreated advanced cases carry a higher risk of permanent vision loss, so keeping to follow-up intervals matters. The decision isn't based on stage alone — which area is affected matters too, since fluid involving the macula may need earlier intervention than a finding at the periphery. Decisions are made individually, from examination and imaging findings together.

The most common treatment is intravitreal (anti-VEGF) injection therapy, which reduces abnormal vessel growth and fluid build-up and is usually given as a series of injections at set intervals. In more advanced stages, retinal laser treatment and surgery — laser photocoagulation or vitrectomy — may come into play. The approach depends on disease stage and examination findings; some patients need more than one method, together or in sequence. Regular eye examinations continue afterwards too, since the condition can become active again even once controlled.

Age-related macular degeneration and retinal tear or detachment are other retinal diseases worth considering here, since they can cause similar complaints such as eye floaters. A routine, full eye examination in people with diabetes often covers refractive error and cataract development too, so follow-up is usually planned within a comprehensive eye examination.

If you have diabetes and have noticed any recent change in your vision, you can book a consultation for a retina examination.