Diabetic Retinopathy – Diabetic Eye Disease
Diabetic macular oedema · Intravitreal injections · Retinal laser · Prof. Dr. Fırat Helvacıoğlu, FEBOS-CR · Veni Vidi Eye Clinic, Caddebostan – Kadıköy, Istanbul
Diabetic retinopathy is an eye disease in which diabetes damages the retinal blood vessels, and it causes no symptoms in its early stages. It affects about one in five people with diabetes. With blood sugar control, regular dilated eye examinations and, when needed, intravitreal injections (anti-VEGF) or retinal laser, you can prevent most vision loss.
What is diabetic retinopathy?
Diabetic retinopathy is an eye disease in which diabetes damages the small blood vessels of the retina; if left untreated, it can lead to permanent vision loss. Over time, high blood sugar weakens the vessel walls; fluid and blood leak from the vessels, some areas lose their blood supply, and the retina responds by growing abnormal new vessels.
Diabetic retinopathy is one of the leading causes of preventable blindness in working-age adults. According to a global meta-analysis, about 22% of people with diabetes have diabetic retinopathy and 6% have a sight-threatening stage; the number of people with the disease worldwide will likely exceed 160 million by 2045.
Stages: from early disease to the proliferative stage
- Non-proliferative (early) diabetic retinopathy: Microaneurysms, dot haemorrhages and leakage appear in the capillaries. It usually causes no symptoms.
- Diabetic macular oedema: Leakage accumulates in the macula and central vision becomes blurred. It can develop at any stage and is the most common cause of vision loss.
- Proliferative diabetic retinopathy: Fragile new vessels develop in the oxygen-starved retina; vitreous haemorrhage, tractional retinal detachment and neovascular glaucoma may develop.
Stages of diabetic retinopathy: step-by-step illustration
Shows how diabetes affects the retinal vessels, as seen on fundus examination.
- Healthy retinaThe vessels are regular; the macula and the optic nerve head (optic disc) look normal.
- Early stage (NPDR)Tiny bulges in the capillaries (microaneurysms), dot haemorrhages and leakage begin; there are often no symptoms.
- Diabetic macular oedemaLeakage accumulates in the macula; the retina swells, yellow lipid deposits (exudates) form and vision becomes blurred.
- Proliferative stage (PDR)Abnormal new vessels develop in the oxygen-starved retina, creating a risk of bleeding inside the eye and retinal detachment.
Symptoms and risk factors of diabetic retinopathy
In the early stage there are often no symptoms at all; so by the time vision loss begins, the disease may have progressed far. See an ophthalmologist without delay if you notice:
- Blurred or wavy vision, difficulty reading
- Floating black spots or a sudden “smoky curtain” in front of the eye
- Faded colours, reduced night vision
- Sudden loss of vision
Risk factors: longer duration of diabetes, poor blood sugar control (high HbA1c), high blood pressure, high cholesterol, kidney disease, pregnancy and smoking. In type 1 diabetes, studies show that intensive blood sugar control reduces the risk of developing retinopathy by 76% and the progression of existing retinopathy by 54%.
How often should you have an eye examination for diabetic retinopathy?
- Type 2 diabetes: A dilated eye examination at diagnosis, then usually annually if there is no retinopathy.
- Type 1 diabetes: A first examination within 5 years of diagnosis, followed by annual check-ups.
- Pregnancy: More frequent examinations for women with diabetes when planning pregnancy and throughout pregnancy.
- If we detect retinopathy: We shorten the interval to 1–6 months depending on the stage.
At the examination, we dilate the pupil with drops, examine the fundus and take an OCT scan to detect macular oedema. Also, we advise you not to drive for a few hours afterwards.
Treatment of diabetic retinopathy
| Treatment | When? | Goal |
|---|---|---|
| Control of blood sugar, blood pressure and cholesterol | At every stage | To slow disease progression; together with internal medicine/endocrinology |
| Intravitreal injections (anti-VEGF) | Centre-involving diabetic macular oedema; selected proliferative cases | To stop leakage and new vessels, and to preserve or improve vision |
| Intravitreal steroid | Oedema that responds inadequately to injections or where frequent injections are not feasible | To reduce oedema |
| Retinal laser (panretinal photocoagulation) | Proliferative stage | To regress new vessels and reduce the risk of haemorrhage and detachment |
| Vitrectomy surgery | Non-clearing vitreous haemorrhage, tractional detachment | To clear the haemorrhage and flatten the retina |
According to Cochrane reviews, anti-VEGF drugs have replaced laser as the standard treatment for diabetic macular oedema. In the DRCR.net Protocol T trial of 660 patients, vision improved by an average of 10–13 letters (about 2–3 lines) at one year with intravitreal injections. In proliferative retinopathy, laser reduces the risk of severe vision loss by more than half; injection therapy can also be an alternative to laser in suitable patients.
How do we perform an intravitreal injection? We perform the procedure under sterile operating conditions with topical anaesthesia, and it takes a few minutes. First, we clean the eye and surrounding area with an antiseptic solution and hold the eyelids open with a speculum. Then we inject the medication into the eye through the white of the eye with a very fine needle. Most patients feel only slight pressure. You may use antibiotic drops for a few days afterwards; if you notice pain, increasing redness or a drop in vision, seek medical attention immediately. Serious side effects such as infection (endophthalmitis) are rare.
Preventing diabetic retinopathy
- Keep your HbA1c at the target recommended by your doctor.
- Keep your blood pressure and cholesterol under control; stop smoking.
- Do not skip your annual dilated eye examination, even if your vision is good.
- If treatment has started, keep up with your injection and follow-up appointments; interrupting treatment can lose the vision you have gained.
Frequently asked questions
Damage that has already occurred in the retina often does not fully reverse; however, with early diagnosis and regular treatment, you can largely preserve your vision, and many patients with macular oedema see an improvement.
Yes. Diabetic retinopathy may cause no symptoms until an advanced stage; doctors treat the disease much more successfully when they detect it while vision is still good.
Treatment usually starts with monthly injections for the first 3–5 months, and then we extend the intervals according to OCT findings. The total number varies from patient to patient.
The aim of laser treatment is to preserve existing vision and halt progression; however, it usually does not restore vision that you have lost. It may cause some reduction in peripheral and night vision.
Yes, but we should bring retinopathy and macular oedema under control before surgery. If necessary, we plan injection treatment before or together with surgery.
References
- Teo ZL et al. Global prevalence of diabetic retinopathy and projection of burden through 2045: systematic review and meta-analysis. Ophthalmology. 2021;128(11):1580–1591. doi:10.1016/j.ophtha.2021.04.027
- Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329(14):977–986. doi:10.1056/NEJM199309303291401
- Virgili G et al. Anti-vascular endothelial growth factor for diabetic macular oedema: a network meta-analysis. Cochrane Database Syst Rev. 2023;6(6):CD007419. doi:10.1002/14651858.CD007419.pub7
- Diabetic Retinopathy Clinical Research Network; Wells JA et al. Aflibercept, bevacizumab, or ranibizumab for diabetic macular edema. N Engl J Med. 2015;372(13):1193–1203. doi:10.1056/NEJMoa1414264
- Evans JR et al. Laser photocoagulation for proliferative diabetic retinopathy. Cochrane Database Syst Rev. 2014;(11):CD011234. doi:10.1002/14651858.CD011234.pub2
- Writing Committee for the Diabetic Retinopathy Clinical Research Network; Gross JG et al. Panretinal photocoagulation vs intravitreous ranibizumab for proliferative diabetic retinopathy: a randomized clinical trial. JAMA. 2015;314(20):2137–2146. doi:10.1001/jama.2015.15217
This page offers patient information and does not replace an examination or medical assessment. Therefore, we determine the treatment that is right for you after an eye examination and measurements.
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Prof. Dr. Fırat Helvacıoğlu · Veni Vidi Eye Clinic, Bağdat Caddesi No: 257, Caddebostan – Kadıköy, Istanbul, Türkiye
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