# Diabetic retinopathy: symptoms, causes and treatment > Source: World Aid Network — https://worldaidnetwork.org/eye-health/diabetic-retinopathy > Last reviewed: 2026-06-19 ## In short Diabetic retinopathy is damage to the retina — the light-sensitive layer at the back of the eye — caused by high blood sugar harming its tiny blood vessels. It is one of the leading causes of sight loss in working-age adults. Like glaucoma, it often causes no symptoms in its early, most treatable stages, which is why everyone with diabetes is offered regular eye screening. Caught early and combined with good control of blood sugar, blood pressure and cholesterol, most serious sight loss can be prevented. Left unchecked, it can lead to permanent blindness. Diabetic retinopathy is damage to the blood vessels of the retina caused by the effects of chronically elevated blood glucose. It is the leading cause of blindness in working-age adults in the UK and affects approximately 1.7 million people with diabetes to some degree. The condition is almost always symptom-free in its early and moderate stages — meaning people can be losing their sight without knowing it. This is why the NHS provides annual diabetic eye screening to every person with Type 1 or Type 2 diabetes from the age of 12. Regular screening and good diabetes management can prevent sight loss in the vast majority of cases. This guide answers the twenty most commonly searched questions about diabetic retinopathy, drawing on NHS and WHO sources. ## At a glance - Cause: Diabetes damaging the retina - Most affects: Working-age adults - Early symptoms: Often none - Protection: Screening + blood-sugar control ## When to see a doctor - If you have diabetes, attend your eye screening even if your sight feels fine — early damage is invisible - Gradually worsening or fluctuating vision - Spots or dark strings floating in your vision (floaters) - Blurred or patchy vision - URGENT: sudden loss of vision, or a 'curtain' over your sight — seek urgent eye care ## How diabetes damages the eyes Chronically elevated blood glucose damages the walls of the small blood vessels (capillaries) supplying the retina. Damaged capillary walls become leaky, allowing blood and fluid to seep into the retina (causing diabetic macular oedema — the most common cause of diabetes-related vision loss) or becoming blocked, cutting off blood supply. In response to ischaemia (poor blood supply), the retina releases VEGF (vascular endothelial growth factor), stimulating the growth of abnormal new blood vessels (neovascularisation) — a hallmark of proliferative diabetic retinopathy. These abnormal vessels are fragile and grow on the surface of the retina and into the vitreous, where they can bleed (vitreous haemorrhage) and form fibrous scar tissue that pulls on the retina (tractional retinal detachment). Both complications cause sudden, severe vision loss. ## Stages of diabetic retinopathy The NHS classifies diabetic retinopathy into screening grades: R0 (no retinopathy); R1 (background retinopathy — microaneurysms, haemorrhages, hard exudates); R2 (pre-proliferative retinopathy — cotton wool spots, venous beading, intraretinal microvascular abnormalities — IRMA); R3 (proliferative retinopathy — new vessels on disc or elsewhere — high risk of vitreous haemorrhage and tractional detachment; requires urgent treatment); and M (maculopathy — any retinopathy or exudate within one disc diameter of the macula centre, or unexplained visual loss). Proliferative diabetic retinopathy (PDR, grade R3) and diabetic macular oedema (DMO, grade M) are the two main causes of diabetes-related vision loss and require prompt specialist treatment. Many people with diabetic retinopathy have no symptoms in the R1–R2 stages — which is why annual screening is essential. ## Treatment options Diabetic macular oedema (the most common cause of vision loss in diabetes) is treated primarily with intravitreal anti-VEGF injections — ranibizumab and aflibercept are NICE-approved for NHS use. Steroid implants (dexamethasone — Ozurdex) are used in some cases. Laser photocoagulation of the macular area (focal/grid laser) can stabilise macular oedema but is less effective than anti-VEGF at improving visual acuity. Proliferative diabetic retinopathy (new vessel growth) is treated with panretinal photocoagulation (PRP) — laser treatment applied to the peripheral retina to destroy areas of ischaemia and suppress VEGF production, causing regression of new vessels. For advanced PDR with vitreous haemorrhage or tractional retinal detachment, vitrectomy surgery is required. Systemic control — optimising HbA1c, blood pressure and blood lipids — is the foundation of preventing and slowing retinopathy. ## Diabetic retinopathy in the developing world The International Diabetes Federation estimates that approximately 537 million adults worldwide have diabetes, with the majority living in low- and middle-income countries — and these numbers are projected to grow substantially. Pakistan has the third highest absolute number of people with diabetes in the world; Indonesia has the fifth highest. Diabetic retinopathy affects over 103 million people globally and is the fastest-growing cause of preventable blindness across South and South-East Asia — directly striking the populations our charity serves. In high-income countries, annual eye screening, laser treatment and anti-VEGF injections keep the rate of severe diabetic retinopathy relatively low. In low-income countries, diabetes is frequently undiagnosed, retinal screening is almost entirely absent for poor patients, and anti-VEGF drugs and laser facilities are inaccessible without payment. A patient who would be picked up at background retinopathy stage in an NHS screening programme — treated, and their sight preserved — instead progresses silently to proliferative disease and irreversible blindness because they cannot afford a single specialist appointment. The tragedy is that 90% of diabetic blindness is preventable with timely screening and treatment. World Aid Network funds diabetic eye disease treatment — retinal examinations, laser photocoagulation, anti-VEGF injections and vitreoretinal surgery — for poor patients in Pakistan, Indonesia and Malaysia, delivered through locally-licensed ophthalmologists in registered hospitals. Your donation reaches the patient who is losing their sight to a condition that was entirely preventable. ## Key takeaways - Diabetic retinopathy is the leading cause of blindness in working-age adults in the UK, affecting approximately 1.7 million people with diabetes. It is almost always preventable with good diabetes management and annual screening. - Early and moderate retinopathy causes no symptoms. Sight loss can be occurring without any awareness — annual NHS diabetic eye screening is essential for everyone with Type 1 or Type 2 diabetes from age 12. - The two main causes of vision loss are diabetic macular oedema (treated with anti-VEGF injections) and proliferative diabetic retinopathy (treated with panretinal laser photocoagulation). - Good control of blood glucose (HbA1c), blood pressure and blood lipids significantly reduces the risk of developing and progressing retinopathy — more than any treatment can achieve once retinopathy is established. - In low-income countries, widespread diabetes and absent screening infrastructure mean many patients present with advanced, irreversible diabetic retinopathy. ## Frequently asked questions ### What is diabetic retinopathy? Diabetic retinopathy is progressive damage to the blood vessels of the retina caused by chronically elevated blood glucose in people with diabetes. Damaged retinal capillaries become leaky, blocked or proliferate abnormally, leading to retinal oedema, haemorrhage, and — in advanced disease — vitreous bleeding and tractional retinal detachment. It is the leading cause of blindness in working-age adults in the UK. ### What are the symptoms of diabetic retinopathy? In the early stages (background and pre-proliferative retinopathy), diabetic retinopathy causes no symptoms at all — vision is normal despite structural damage occurring. Symptoms appear only in advanced disease: sudden visual disturbance or blurring caused by vitreous haemorrhage; a dark area or shadow in vision; floaters (blood in the vitreous); distorted or blurred central vision (diabetic macular oedema); and, rarely, sudden complete vision loss from tractional retinal detachment. The absence of symptoms in early disease makes annual screening essential. ### Does everyone with diabetes get retinopathy? Not everyone with diabetes develops sight-threatening retinopathy, but most people with longstanding diabetes develop some degree of retinal change. After 20 years of Type 1 diabetes, over 90% of patients have some retinopathy; in Type 2 diabetes, approximately 60% have some retinopathy after 20 years. The risk is directly related to the duration of diabetes, blood glucose control (HbA1c), blood pressure control and kidney function. Good control dramatically reduces but does not eliminate risk. ### How common is diabetic retinopathy in the UK? Approximately 1.7 million people in the UK have some degree of diabetic retinopathy. Of these, around 200,000 have sight-threatening retinopathy requiring active treatment. Diabetic retinopathy is the leading cause of blindness among people of working age in the UK — a preventable tragedy, since most vision loss from diabetes is avoidable with appropriate screening, monitoring and treatment. ### What causes diabetic retinopathy? Sustained elevated blood glucose damages the endothelial cells lining retinal capillaries, causing them to become leaky, develop microaneurysms (small balloon-like swellings) and eventually become blocked. These changes lead to retinal ischaemia (poor blood supply), which triggers VEGF release — stimulating growth of fragile abnormal new blood vessels (neovascularisation) that bleed and scar. High blood pressure and high blood lipids compound the damage. ### What are the stages of diabetic retinopathy? The NHS diabetic eye screening programme grades retinopathy as: R0 — no retinopathy; R1 — background retinopathy (microaneurysms, haemorrhages, hard exudates) — no immediate treatment needed, annual screening continues; R2 — pre-proliferative retinopathy (cotton wool spots, venous beading, IRMA) — referred to hospital ophthalmology for closer monitoring; R3 — proliferative retinopathy (new vessel growth) — urgent treatment required; M — maculopathy (changes threatening central vision) — urgent referral. R3 and M require specialist intervention. ### What is diabetic macular oedema (DMO)? Diabetic macular oedema (DMO) is swelling of the macula — the central, high-resolution area of the retina — caused by leakage of fluid from damaged retinal blood vessels. It is the most common cause of vision loss in diabetic retinopathy, causing blurred or distorted central vision. DMO can occur at any stage of retinopathy and is graded as maculopathy (M) in the NHS screening system. It is treated with anti-VEGF intravitreal injections, which are NICE-approved for NHS use. ### What is the NHS diabetic eye screening programme? The NHS Diabetic Eye Screening Programme (DESP) offers annual photographic retinal screening to all people aged 12 and over with Type 1 or Type 2 diabetes. Retinal photographs are taken with a fundus camera (usually without dilation) and graded by trained screeners and ophthalmologists. People with R0 or R1 screening results continue annual screening; people with R2, R3 or M are referred to hospital ophthalmology. The programme has significantly reduced the number of people losing their sight to diabetic retinopathy in the UK. ### How is diabetic retinopathy treated? Treatment depends on the type and severity. Diabetic macular oedema: anti-VEGF injections (ranibizumab/aflibercept) — NICE-approved — given monthly initially then as needed; dexamethasone implant (Ozurdex) for some patients; focal laser as an adjunct. Proliferative retinopathy (R3): panretinal laser photocoagulation (PRP) — laser burns applied to the peripheral retina to suppress new vessel growth. Advanced PDR (vitreous haemorrhage, tractional detachment): vitrectomy surgery. Systemic: optimise HbA1c, blood pressure and lipids — the most important intervention of all. ### Can diabetic retinopathy be reversed? Structural changes to the retina caused by diabetic retinopathy cannot generally be reversed. However, anti-VEGF treatment for diabetic macular oedema can resolve retinal swelling and improve visual acuity significantly — and panretinal laser causes new vessel regression in proliferative retinopathy, preventing further bleeding. Good glycaemic control can slow or halt progression and, in some cases, allow early retinal changes to improve. Vision that has been permanently lost due to photoreceptor or retinal nerve fibre damage cannot be restored. ### What is panretinal photocoagulation (PRP)? Panretinal photocoagulation (PRP) is a laser treatment for proliferative diabetic retinopathy. A laser is applied to the peripheral retina in hundreds to thousands of small burns over one or two sessions. This destroys ischaemic peripheral retinal tissue, reducing its VEGF output and causing the abnormal new vessels to regress. PRP prevents vitreous haemorrhage and tractional retinal detachment. It may cause some reduction in peripheral vision, night vision and colour discrimination — a trade-off considered worthwhile to prevent proliferative disease from causing total blindness. ### What is a vitrectomy? Vitrectomy is a surgical procedure to remove the vitreous gel from inside the eye. It is used in diabetic retinopathy for: vitreous haemorrhage that has not cleared spontaneously (blood obscuring vision); tractional retinal detachment caused by fibrovascular scar tissue pulling on the retina; and combined tractional-rhegmatogenous retinal detachment. During vitrectomy, the surgeon also peels fibrovascular membranes from the retina and may apply endolaser. Vision outcomes depend on whether the macula has been involved in the detachment. ### How can I prevent diabetic retinopathy? The most important preventive measures are: optimising blood glucose control (target HbA1c <53 mmol/mol or <7% for most patients — agreed individually with your diabetes team); controlling blood pressure (target typically below 130/80 mmHg); managing blood lipids with statins as appropriate; not smoking; maintaining a healthy weight; attending annual NHS diabetic eye screening; and following up promptly if referred to hospital ophthalmology. Intensive glucose control reduces the risk of retinopathy development by approximately 76% in Type 1 diabetes (DCCT trial data). ### Can Type 2 diabetes cause diabetic retinopathy? Yes. Both Type 1 and Type 2 diabetes cause diabetic retinopathy. In Type 2 diabetes, retinopathy may already be present at diagnosis — because the condition often develops gradually and may have been undiagnosed for years before formal diagnosis. After 20 years of Type 2 diabetes, approximately 60% of patients have some retinopathy. Type 2 diabetes-associated retinopathy is treated with the same approach as Type 1 — screening, glucose and blood pressure control, and laser or anti-VEGF as needed. ### What is the difference between diabetic retinopathy and diabetic macular oedema? Diabetic retinopathy is the umbrella term for all retinal changes caused by diabetes — from the earliest microaneurysms to advanced proliferative disease. Diabetic macular oedema (DMO) is a specific complication in which fluid accumulates in the macula (the central retina), causing blurred or distorted central vision. DMO can occur at any stage of retinopathy — including in early background retinopathy — and does not require proliferative disease to be present. DMO is the most common cause of vision loss in diabetes and the primary indication for anti-VEGF treatment. ### What are the risk factors for diabetic retinopathy? The key risk factors for developing and progressing diabetic retinopathy are: longer duration of diabetes (the most important factor); poor blood glucose control (high HbA1c); high blood pressure; high blood lipids (particularly triglycerides); diabetic nephropathy (kidney disease); pregnancy in women with diabetes; puberty (accelerates retinopathy in Type 1); smoking; and a family history of retinopathy. Each of these is modifiable to some degree — which is why diabetic retinopathy is largely preventable. ### Is diabetic eye screening the same as a regular eye test? No. NHS diabetic eye screening and a regular optician's eye test are different. The NHS DESP focuses specifically on photographing the retina to grade diabetic retinopathy and maculopathy — it does not check glasses prescription, measure eye pressure or assess the full eye. A regular optician's eye test checks vision, eye pressure, optic disc and general eye health but is not a substitute for the DESP. People with diabetes should attend both their annual DESP appointment and regular optician eye tests. ### Can diabetic retinopathy cause total blindness? Without treatment, advanced proliferative diabetic retinopathy and untreated diabetic macular oedema can cause severe and permanent vision loss. Vitreous haemorrhage causes sudden visual obscuration; tractional retinal detachment can result in severe, irreversible vision loss if the macula is involved. However, with regular screening and appropriate treatment, the vast majority of sight-threatening diabetic retinopathy can be managed effectively and severe vision loss prevented. ### How does diabetic retinopathy affect people in developing countries? Diabetes is a rapidly growing global epidemic, with the largest increases in low- and middle-income countries. In these settings, diabetes is frequently undiagnosed; retinal photography screening programmes are largely absent; anti-VEGF drugs and laser facilities are unavailable to the rural poor; and patients commonly present with advanced, irreversible retinopathy. World Aid Network funds eye care through locally-licensed ophthalmologists, helping to provide access to sight-saving treatment for people who would otherwise have none. ## How you can help World Aid Network funds sight-restoring eye care for poor patients in Pakistan, Indonesia and Malaysia through locally-licensed surgeons. Donate at https://worldaidnetwork.org/donate --- This is general information, not medical advice, published by World Aid Network. Always consult a qualified clinician about your own health.