Diabetic retinopathy — causes, diagnosis, treatment, and prevention

Types and underlying changes

Retinopathy is often categorized into two broad forms. Nonproliferative diabetic retinopathy (NPDR) ranges from mild to severe and is characterized by microaneurysms, dot‑blot hemorrhages, hard exudates and cotton‑wool spots. Proliferative diabetic retinopathy (PDR) is advanced disease driven by retinal ischemia and marked by neovascularization — fragile new vessels that can bleed into the vitreous or cause tractional retinal detachment. Diabetic macular edema (DME) can occur at any stage when fluid accumulates in the macula, the central area responsible for sharp vision.

Risk factors and progression

Key risk factors include duration of diabetes, poor glycemic control, high blood pressure, elevated blood lipids, pregnancy, and kidney disease. The likelihood of retinopathy increases with time: many people with ten or more years of diabetes develop some retinal changes. With early detection and appropriate treatment, substantial vision loss can often be prevented; some estimates indicate a large proportion of new severe cases are avoidable with timely care.

Signs, diagnosis, and screening

Early disease is frequently asymptomatic. When symptoms occur they may include floaters, blurred or fluctuating vision, and progressive loss of central vision. Diagnosis is made by a dilated eye examination and may be supplemented by optical coherence tomography (OCT) to measure macular swelling and by fluorescein angiography to map leaking or ischemic vessels. Clinical guidelines generally recommend regular dilated retinal exams for people with diabetes; frequency depends on type and duration of diabetes and on prior retinal findings.

Treatments and prevention

Treatment aims to preserve vision and address causes of retinal damage. Measures to slow onset and progression include strict glycemic control, blood pressure and lipid management, and smoking cessation. Medical and surgical eye treatments include:

• Anti‑VEGF injections (vascular endothelial growth factor inhibitors such as ranibizumab, aflibercept, or bevacizumab) to reduce macular swelling and regress abnormal vessels.
• Laser photocoagulation — focal/grid laser for macular edema and panretinal photocoagulation for proliferative disease to reduce risk of severe vision loss.
• Vitrectomy — surgery to clear persistent vitreous hemorrhage or relieve tractional detachment.

Prognosis and public health

With modern treatments and systematic screening, many patients maintain functional vision, but untreated advanced retinopathy can progress to severe visual impairment or blindness. Public health approaches emphasize prevention through metabolic control and organized screening programmes to identify treatable disease early. Regular follow‑up and coordination between primary care, diabetes specialists, and eye care professionals are central to reducing the burden of diabetic retinal disease.