clinical features

Last reviewed 01/2018

  • microaneurysms are the earliest signs:
    • they are outpouchings of the capillaries, which appear as minute, sharply circumscribed, red dots, and are distinguished from haemorrrhages by their usual location far from blood vessels and their sharp border
    • many are too small to be visualised with the ophthalmoscope and are apparent only following fluorescein angiography

  • dot and blot haemorrhages:
    • occur within the inner nuclear layer of the retina where cells are so compactly arranged that the haemorrhage cannot spread

  • flame shaped haemorrhages:
    • in the nerve fibre layer - their shape reflects the nerve fibre distribution

  • retinal oedema:
    • due to capillary leakage - with a predilection for the macula

  • hard exudates:
    • yellow, lipid precipitates which result from resorption of retinal oedema

  • in general vision is normal; however central vision is variably impaired if changes affect the fovea - note the fovea is capillary free