Diabetic retinopathy

Diabetic retinopathy
Name	Diabetic retinopathy
Field	Ophthalmology, Endocrinology
Symptoms	Often asymptomatic early; can progress to blurred vision, floaters, vision loss
Complications	Vitreous hemorrhage, Retinal detachment, Neovascular glaucoma, blindness
Duration	Chronic
Causes	Long-term diabetes; associated with hyperglycemia
Risks	Duration of diabetes, poor glycemic control, hypertension, hyperlipidemia, pregnancy, nephropathy
Diagnosis	Dilated fundus examination, fundus photography, optical coherence tomography, fluorescein angiography
Treatment	Glycemic control, blood pressure control, anti-VEGF injections, laser photocoagulation, vitrectomy
Prevention	Glycemic control, regular dilated eye examinations, management of hypertension and hyperlipidemia
Frequency	Leading cause of blindness among working-age adults in the United States

Diabetic retinopathy is a common microvascular complication of diabetes mellitus and a leading cause of vision impairment globally. It results from damage to the blood vessels of the light-sensitive tissue at the back of the eye, the retina. The condition is often asymptomatic in its early stages but can progress to severe vision loss if not managed through regular screening and timely intervention.

Signs and symptoms

In its non-proliferative stages, patients are frequently asymptomatic, with changes detectable only through ophthalmoscopy. As the disease advances, symptoms may include blurred or fluctuating vision, the perception of dark spots or floaters, impaired color vision, and sudden vision loss. Severe complications like vitreous hemorrhage or tractional retinal detachment can cause profound, acute visual deficits, while macular edema is a common cause of central vision blurring.

Causes and risk factors

The primary cause is chronic hyperglycemia associated with diabetes mellitus, both type 1 and type 2. Major modifiable risk factors include prolonged poor glycemic control and the presence of hypertension. Other significant risk factors are the duration of diabetes, hyperlipidemia, co-existing diabetic nephropathy, and pregnancy in women with pre-existing diabetes. Genetic predisposition and factors like smoking may also influence disease severity and progression.

Pathophysiology

The pathophysiology is driven by chronic hyperglycemia, which leads to damage of the retinal capillary endothelium and pericyte loss, a process studied extensively by organizations like the National Institutes of Health. This results in increased vascular permeability, causing retinal edema and hard exudate formation in non-proliferative diabetic retinopathy. Hypoxia from capillary closure then triggers a cascade involving growth factors like vascular endothelial growth factor, leading to pathological neovascularization and the proliferative stage, which carries a high risk of vitreous hemorrhage and fibrovascular proliferation.

Diagnosis

Diagnosis is primarily made through a comprehensive dilated fundus examination by an ophthalmologist or optometrist. Key diagnostic tools include fundus photography, often used in screening programs like those by the National Health Service, and optical coherence tomography to assess macular edema. Fluorescein angiography is utilized to evaluate vascular leakage and ischemia. The disease is classified into stages such as mild or moderate non-proliferative diabetic retinopathy, severe non-proliferative diabetic retinopathy, and proliferative diabetic retinopathy.

Treatment

Management depends on disease severity and centers on systemic control of glycemia and blood pressure. For vision-threatening stages, treatments include intravitreal injections of anti-VEGF agents like ranibizumab or aflibercept, and corticosteroids such as dexamethasone. Laser photocoagulation, particularly panretinal photocoagulation, remains a standard treatment for proliferative disease. Advanced complications like non-clearing vitreous hemorrhage or tractional retinal detachment may require surgical vitrectomy.

Prevention

Primary prevention focuses on stringent glycemic control, as demonstrated by major trials like the Diabetes Control and Complications Trial and the United Kingdom Prospective Diabetes Study. Secondary prevention involves regular dilated eye examinations as recommended by the American Diabetes Association and management of associated hypertension and hyperlipidemia. Public health initiatives by bodies like the World Health Organization emphasize screening to detect asymptomatic disease early.

Epidemiology

It is a major global public health concern and the leading cause of blindness among working-age adults in developed countries such as the United States and the United Kingdom. Prevalence increases directly with the duration of diabetes; most individuals with type 1 diabetes and over 60% of those with type 2 diabetes develop some degree of retinopathy after two decades. The burden is rising worldwide in parallel with the increasing prevalence of diabetes mellitus.

Category:Diabetes Category:Eye diseases Category:Disabilities