Diabetic Retinopathy

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Intro & Pathophysiology - Sweet Retinal Damage

  • Diabetic Retinopathy (DR): Most common microvascular complication of Diabetes Mellitus (DM). A leading cause of preventable blindness in working-age adults globally.
  • Pathophysiology: Driven by chronic hyperglycemia.
    • Key mechanisms:
      • Polyol pathway: Aldose reductase converts glucose to sorbitol → osmotic stress, cellular damage.
      • Advanced Glycation End-products (AGEs): Accumulate, causing vascular dysfunction, ↑permeability.
      • Protein Kinase C (PKC) activation: Stimulates VEGF, promoting angiogenesis and leakage.

⭐ Pericyte loss is the earliest detectable histological change in diabetic retinopathy.

  • Consequences: Breakdown of Blood-Retinal Barrier (BRB), capillary non-perfusion, retinal ischemia/hypoxia, leading to VEGF upregulation.

Classification & Features - Retina's Red Alerts

  • Non-Proliferative DR (NPDR): No neovascularization.
    • Mild: ≥1 Microaneurysm (MA).
    • Moderate: MAs, dot/blot hemorrhages (H), hard exudates (HE), Cotton Wool Spots (CWS). Not severe NPDR.
    • Severe (4-2-1 Rule): Any 1 of:
      • Severe H/MA in 4 quadrants.
      • Venous beading (VB) in ≥2 quadrants.
      • IRMA (Intraretinal Microvascular Abnormalities) in ≥1 quadrant.
    • Very Severe: ≥2 criteria for severe NPDR.
  • Proliferative DR (PDR): Neovascularization (NV) present.
    • NVD (NV of Disc) / NVE (NV Elsewhere).
    • Complications: Vitreous hemorrhage, Tractional Retinal Detachment (TRD).
  • Diabetic Macular Edema (DME): Macular thickening/exudates. Commonest cause of vision loss. Can occur at any stage.

    ⭐ Neovascularization (NVD/NVE) is the hallmark of Proliferative Diabetic Retinopathy (PDR). Fundus findings in NPDR stages and PDR with NVD/NVEoka

Diagnosis & Investigations - Eye Detective Tools

  • Dilated Fundoscopy: Essential first step. Identifies microaneurysms, hemorrhages, hard exudates, cotton wool spots, IRMA, NVD, NVE.
  • Key Imaging Modalities:
    • Fundus Photography: Baseline documentation; monitors progression.
    • Optical Coherence Tomography (OCT): Gold standard for DME detection & quantification; measures central macular thickness.
    • Fluorescein Angiography (FFA): Visualizes retinal circulation; detects leakage, macular ischemia, neovascularization. Critical for PDR.
    • OCT Angiography (OCT-A): Non-invasive; details microvasculature; alternative to FFA.
  • Systemic Evaluation: Crucial for management: HbA1c, blood pressure, lipid profile, renal function. Diabetic Retinopathy Stages

⭐ Fluorescein Angiography (FFA) is crucial for detecting neovascularization and macular ischemia.

Management - Sight-Saving Tactics

  • Core Aim: Prevent vision loss; stabilize/improve sight.
  • Systemic Control: Essential foundation.
    • Glycemic (HbA1c < 7%), BP (< 140/90 mmHg), Lipid optimization.
  • Ocular Therapies: Tailored to severity.
    • Laser Photocoagulation:
      • PRP (Pan-Retinal): For PDR, severe NPDR. Reduces neovessels.
      • Focal/Grid: For specific DME (less common).
    • Anti-VEGF Injections: (Ranibizumab, Aflibercept)
      • First-line for center-involving DME. Reduces permeability.
      • Adjunct for PDR.
    • Intravitreal Steroids: (Dexamethasone implant) Refractory DME; pseudophakic.
    • Pars Plana Vitrectomy (PPV):
      • Non-clearing vitreous hemorrhage.
      • Tractional RD involving macula.

⭐ Pan-Retinal Photocoagulation (PRP) is the gold standard treatment for high-risk PDR.

Fundus with PRP laser scars

Screening & Prevention - Vision Vigilance Now

  • Regular dilated fundus examination is paramount.

    ⭐ Annual dilated eye exam recommended for all diabetics: at diagnosis for Type 2 DM, and 5 years after diagnosis for Type 1 DM.

  • Primary Prevention Pillars:
    • Intensive glycemic control (Target HbA1c < 7%).
    • Optimal blood pressure management (Target < 140/90 mmHg).
    • Dyslipidemia correction.
  • Counsel on early symptom recognition and treatment adherence.

High‑Yield Points - ⚡ Biggest Takeaways

  • Diabetic Retinopathy (DR): leading cause of new blindness in working-age individuals.
  • Duration of diabetes: most significant risk factor for DR development.
  • Microaneurysms are the earliest sign of NPDR; also see hemorrhages, exudates, CWS.
  • PDR is marked by neovascularization (NVD/NVE), risking vitreous hemorrhage and TRD.
  • Macular Edema (CSME): can occur at any stage, primary cause of visual impairment.
  • Pan-Retinal Photocoagulation (PRP): standard treatment for high-risk PDR.
  • Anti-VEGF injections: vital for macular edema and adjunctive in PDR.

Practice Questions: Diabetic Retinopathy

Test your understanding with these related questions

Retinopathy is most likely to be seen with which of the following conditions?

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Flashcards: Diabetic Retinopathy

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ETDRS stands for _____ Treatment for Diabetic Retinopathy Study.

TAP TO REVEAL ANSWER

ETDRS stands for _____ Treatment for Diabetic Retinopathy Study.

Early

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