OcuLearning › Retina

Diabetic Retinopathy

ROUTINE — Retina

Symptoms

often asymptomatic in early stages

blurred or fluctuating vision from macular edema

sudden vision loss or floaters from vitreous hemorrhage

progressive vision loss from tractional retinal detachment

Clinical Findings

NPDR

  • microaneurysms and dot-blot hemorrhages
  • hard exudates and cotton-wool spots
  • venous beading and intraretinal microvascular abnormalities (irma)

PDR

  • neovascularization of the disc (nvd) or elsewhere (nve)
  • preretinal or vitreous hemorrhage
  • fibrovascular proliferation and tractional retinal detachment

Diabetic macular edema (DME)

  • retinal thickening or hard exudates within 1 disc diameter of the fovea
  • center-involving if fovea is thickened on oct

Staging (4-2-1 rule for severe NPDR)

  • >20 intraretinal hemorrhages in 4 quadrants
  • venous beading in 2 quadrants
  • irma in 1 quadrant

Etiology

Mechanism

  • chronic hyperglycemia damages retinal capillary pericytes
  • capillary non-perfusion and ischemia drive vegf release

Risk factors

  • duration of diabetes (strongest risk factor)
  • poor glycemic control (hba1c), hypertension, and dyslipidemia
  • pregnancy, nephropathy, and smoking
  • early worsening: transient progression risk during rapid tightening of glycemic control

Red Flags

vitreous hemorrhage or tractional retinal detachment

neovascular glaucoma (nvi with elevated iop and pain)

center-involving dme with acute vision drop

pregnancy with pre-existing dr (high risk of rapid progression)

Investigations

Ocular examination

  • gonioscopy: perform before dilation to assess for nvi and nva
  • slit lamp (90d/60d): rule out neovascularization and macular edema
  • indirect ophthalmoscopy: examine the retinal periphery

Imaging

  • oct: assess presence and extent of dme
  • ivfa: identify perfusion abnormalities, foveal ischemia, and subclinical neovascularization
  • octa: assess central macular ischemia

Systemic

  • fasting blood sugar, hba1c, and lipid panel
  • blood pressure monitoring

Treatment

Systemic optimization

  • hba1c <7%: ~35% microvascular risk reduction per 1% drop
  • blood pressure <130/80 mmhg: reduces dr progression by ~34%
  • lipid control: statins and fenofibrate (reduces progression independently of lipids)

Diabetic macular edema

  • anti-vegf: first-line for center-involving dme (aflibercept, ranibizumab, bevacizumab)
  • steroids: dexamethasone or fluocinolone implants (second-line; watch for cataract/iop)
  • focal macular laser: for extrafoveal microaneurysms causing edema

Proliferative DR

  • panretinal photocoagulation (prp): durable, single-session for non-adherent patients
  • anti-vegf: non-inferior to prp with better peripheral field preservation
  • combination: anti-vegf plus prp for concurrent dme or dense vitreous hemorrhage

Vitrectomy indications

  • dense, non-clearing vitreous hemorrhage
  • tractional rd involving or threatening the macula
  • dense premacular hemorrhage or chronic refractory dme

Differential Diagnosis

  • central retinal vein occlusion (crvo)
  • hypertensive retinopathy
  • sickle cell retinopathy
  • ocular ischemic syndrome
  • hypercoagulable states

Related Retina Conditions