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Diabetic Retinopathy

Diabetic Retinopathy is a microvascular complication of diabetes mellitus that damages the retinal blood vessels, leading to retinal ischemia, vascular leakage, macular edema, and, in advanced disease, abnormal new blood vessel formation.

Also called

Diabetic Eye Disease

ICD-10

E10.3 + E11.3

Specialty

Endocrine

Onset

Chronic

Reviewed

August 2026

On This Page

Overview

    • Diabetic retinopathy develops due to chronic hyperglycemia causing progressive damage to the retinal microvasculature.

 

    • The disease is broadly divided into:
    • Non-Proliferative Diabetic Retinopathy (NPDR): early stage characterized by retinal vascular leakage and microvascular abnormalities.

 

    • Proliferative Diabetic Retinopathy (PDR): advanced stage characterized by retinal neovascularization.
    • Diabetic macular edema (DME) can occur at different stages and is an important cause of visual impairment.

Etiology & Risk Factors

-Etiology:

The main underlying cause is chronic hyperglycemia, which causes:

  • Retinal capillary endothelial injury
  • Pericyte loss
  • Increased vascular permeability
  • Capillary closure
  • Retinal ischemia
  • Increased vascular endothelial growth factor (VEGF)
  • Retinal neovascularization

 

-Risk Factors:

  • Long duration of diabetes
  • Poor glycemic control
  • Hypertension
  • Dyslipidemia
  • Chronic kidney disease
  • Smoking
  • Rapid improvement in glycemic control in some patients with established retinopathy

Pathophysiology

Chronic hyperglycemia → retinal microvascular injury → pericyte loss + endothelial dysfunction → capillary leakage and microaneurysm formation → capillary closure → retinal ischemia → increased VEGF → retinal neovascularization → fragile new vessels → vitreous hemorrhage + fibrosis → tractional retinal detachment

 

Retinal vascular leakage → macular fluid accumulation → diabetic macular edema → impaired central vision

Clinical Presentation

–Early disease is often asymptomatic.

-Possible symptoms include:

  • Blurred vision
  • Fluctuating vision
  • Difficulty reading
  • Reduced visual acuity
  • Floaters
  • Dark spots in the visual field

 

-Signs:

Non-Proliferative Diabetic Retinopathy:

  • Microaneurysms
  • Retinal hemorrhages
  • Hard exudates
  • Cotton-wool spots
  • Venous abnormalities

 

-Proliferative Diabetic Retinopathy:

  • Retinal neovascularization
  • New vessels on the optic disc
  • New vessels elsewhere on the retina
  • Fibrovascular proliferation

-Diabetic Macular Edema

  • Retinal thickening
  • Intraretinal fluid
  • Reduced central visual acuity

 

-Severe Disease

  • Severe visual impairment
  • Vitreous hemorrhage
  • Tractional retinal detachment
  • Neovascular glaucoma
  • Permanent vision loss

History Taking

-Ask about:

  • Duration of diabetes
  • Type of diabetes
  • Glycemic control
  • HbA1c
  • Previous retinal screening
  • Previous diagnosis of diabetic retinopathy
  • Previous laser or intravitreal treatment
  • Blurred vision
  • Floaters
  • Sudden visual loss
  • Distorted vision
  • Difficulty reading

Physical Examination

–General Examination

  • Blood pressure
  • Glycemic control assessment
  • Body mass index
  • Assessment for other diabetic complications

 

-System-Specific Examination

 

-Eye Examination

  • Assess:
  • Visual acuity
  • Pupillary responses
  • Anterior segment
  • Intraocular pressure
  • Fundus examination

 

–Fundoscopic findings may include:

  • Microaneurysms
  • Dot-blot hemorrhages
  • Hard exudates
  • Cotton-wool spots
  • Venous beading
  • Intraretinal microvascular abnormalities

Investigations

-Biochemistry / Specific Tests

  • HbA1c
  • Fasting or random plasma glucose
  • Blood pressure measurement
  • Renal function
  • Urine albumin-to-creatinine ratio
  • Lipid profile

 

These help assess overall diabetic and cardiovascular risk.

-Imaging

Optical Coherence Tomography (OCT)

Important for evaluating:

  • Diabetic macular edema
  • Retinal thickness
  • Intraretinal fluid
  • Subretinal fluid

-Fundus Photography

Used for:

  • Screening
  • Documentation
  • Monitoring progression

-Fluorescein Angiography

May be used to evaluate:

  • Retinal ischemia
  • Vascular leakage
  • Neovascularization
  • Macular pathology

Diagnosis

-Diagnosis is primarily established by ophthalmic examination, particularly dilated fundus examination.

-Findings are classified into:

-Non-Proliferative Diabetic Retinopathy

  • Mild NPDR
  • Moderate NPDR
  • Severe NPDR

-Proliferative Diabetic Retinopathy

  • Retinal or optic-disc neovascularization
  • Fibrovascular proliferation
  • Advanced complications

Diabetic macular edema should be assessed separately because it can occur with both NPDR and PDR.

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Management

1. First-Line / Emergency Management

Most diabetic retinopathy does not require emergency treatment.

Urgent ophthalmological assessment is required for:

  • Sudden visual loss
  • New dense floaters
  • Suspected vitreous hemorrhage
  • Suspected retinal detachment
  • Acute painful visual loss suggesting neovascular glaucoma or another ocular emergency

2. Definitive Treatment

Management depends on the stage:

  • Optimize systemic diabetic control
  • Treat diabetic macular edema when clinically significant
  • Treat high-risk proliferative disease
  • Monitor mild and moderate disease appropriately

3. Medical Treatment

-Intravitreal Anti-VEGF Therapy

Common agents include:

  • Aflibercept
  • Ranibizumab
  • Bevacizumab

Used particularly for:

  • Diabetic macular edema
  • Proliferative disease in selected patients

-Intravitreal Corticosteroids

May be considered in selected patients with diabetic macular edema, particularly when anti-VEGF therapy is unsuitable or inadequate.

4. Surgical / Procedural Treatment

-Panretinal Photocoagulation (PRP)

Important treatment for selected patients with proliferative diabetic retinopathy.

It reduces ischemic retinal drive for neovascularization.

5. Supportive Management

  • Optimize glycemic control
  • Control blood pressure
  • Smoking cessation

Complications

  • Diabetic macular edema
  • Vitreous hemorrhage
  • Tractional retinal detachment
  • Neovascular glaucoma
  • Severe visual impairment
  • Permanent blindness
  • Cataract may occur more frequently in patients with diabetes

Prognosis

-The prognosis depends on:

  • Duration of diabetes
  • Glycemic control
  • Blood pressure control
  • Severity of retinopathy
  • Presence of diabetic macular edema
  • Presence of retinal ischemia

Early detection and appropriate treatment can substantially reduce the risk of severe visual loss.

Key Points / Clinical Pearls

  • Diabetic retinopathy is a microvascular complication of diabetes affecting the retina.
  • Chronic hyperglycemia causes retinal capillary damage and ischemia.
  • Early diabetic retinopathy may be completely asymptomatic.
  • The disease is divided into non-proliferative and proliferative stages.
  • Microaneurysms are often the earliest visible clinical finding.
  • NPDR may show hemorrhages, hard exudates, cotton-wool spots, venous abnormalities, and intraretinal microvascular abnormalities.
  • Proliferative diabetic retinopathy is defined by retinal neovascularization.
  • Retinal ischemia increases VEGF, promoting abnormal new vessel formation.
  • Anti-VEGF therapy is an important treatment for diabetic macular edema and selected proliferative disease.
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  • Wong TY, Cheung CMG, Larsen M, Sharma S, Simó R. Diabetic Retinopathy. Nat Rev Dis Primers. 2016;2:16012. Nature Reviews Disease Primers .
  • Solomon SD, Chew E, Duh EJ, et al. Diabetic Retinopathy: A Position Statement by the American Diabetes Association. Diabetes Care. 2017;40(3):412-418. Diabetes Care .
  • National Eye Institute (NIH). Diabetic Retinopathy . National Institutes of Health.
  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Diabetic Eye Disease . National Institutes of Health.