Hard Exudates

Hard exudates in the posterior pole of an eye with diabetic macular edema. 

  • Hard exudates can be seen in any conditions that are associated with chronic vascular leakage , such as:
    • Diabetic retinopathy
    • Hypertensive retinopathy
    • Coat's disease
    • Capillary hemangioma of the retina
    • Choroidal neovascularization
    • Retinal arterial macroaneurysm

Mechanism:

  • Increased vascular permeability allowing the leakage of fluid and lipoprotein into the retina resulting in thickening of the macula
  • Resorption of the edema commonly results in precipitation of lipid residues within the outer plexiform (Henle's) layer

Clinical features:

  • Symptoms: various degree of decreased vision if involving the macula
  • Signs:
    • Discrete white-yellow lipid deposits in the posterior pole
    • Commonly seen in a circinate pattern peripheral to the areas of leakage
    • May present as large, confluent exudation
    • Macular star and/or circumpapillary hard exudates can be seen in Leber's stellate neuro-retinitis or end-stage hypertensive retinopathy
  • Management: treat the underlying diseases.