Ophthalmic Complications of Diabetes

Major Ocular Complications of Diabetes

  • Diabetic Retinopathy (DR): The most significant microvascular complication and a leading cause of blindness in working-age individuals.

  • Cataracts: Diabetics have a 60%60\% higher risk than the general population. Visual loss is reversible with surgery, provided DR is managed.

  • Glaucoma: Increased risk of Primary Open Angle Glaucoma. Neovascular Glaucoma (secondary angle closure) can occur due to severe ischemia and has a poor prognosis.

  • Ocular Surface Disease: Includes dry eye and corneal epithelial abnormalities, leading to delayed wound healing.

Diabetic Retinopathy (DR) Risk Factors and Pathogenesis

  • Risk Factors: Duration of diabetes (most significant, non-modifiable), glycemic control, and blood pressure control (both modifiable).

  • Pathogenesis:

    • Chronic hyperglycemia leads to pericyte loss (causing microaneurysms), endothelial loss (increasing permeability), and basement membrane thickening.

    • VEGF (Vascular Endothelial Growth Factor): Upregulated by ischemia/hypoxia, leading to angiogenesis (new vessel growth) and further vascular permeability.

Clinical Signs and Grading of Retinopathy

  • Non-Proliferative DR (NPDR) Signs:

    • Microaneurysms: Earliest clinical sign (small red dots).

    • Intraretinal Hemorrhages: Small to large bleeding within the retina.

    • Cotton Wool Spots: Pale, fluffy lesions caused by axoplasmic stasis (not exudation).

    • Hard Exudates: Yellow lipid residues associated with macular edema.

    • Venous Beading and IRMA (Intraretinal Microvascular Abnormalities): Indicators of severe NPDR.

  • Proliferative DR (PDR): Characterized by neovascularization on the optic disc (NVD) or elsewhere (NVE).

  • Diabetic Macular Edema (DME): Retinal thickening that can occur at any stage of DR. Center-involving DME (affecting the fovea) is the primary cause of vision loss.

Imaging and Diagnosis

  • Fundus Photography: Used for documentation and telemedicine screening.

  • Optical Coherence Tomography (OCT): Provides high-resolution cross-sectional images to measure retinal thickness; vital for managing DME.

  • Fluorescein Angiography: An invasive test using dye to assess retinal non-perfusion and vascular leakage.

Treatment Modalities

  • Intravitreal anti-VEGF Injections: The mainstay for DME and PDR. Inhibits angiogenesis and reduces permeability. Multiple, long-term treatments are often required.

  • Laser Panretinal Photocoagulation (PRP): Ablates ischemic peripheral retina to reduce VEGF drive. Used to treat PDR; can reduce peripheral/night vision but helps prevent total blindness.

  • Intravitreal Steroids: Second-line treatment for DME to address inflammation.

  • Vitrectomy: Surgery required for advanced complications such as non-resolving vitreous hemorrhage or tractional retinal detachment.

Coordination of Care

  • Screening: Essential because patients are often asymptomatic in early stages. Over 90%90\% of vision loss from DR is avoidable.

  • Multidisciplinary Management: Coordination between the Ophthalmologist, GP, and Endocrinologist is critical to optimize glycemic control and ensure regular ocular assessment adherence.