caused by chronic localized retinal oedema and develop at the junction of normal and oedematous retina.They are composed of lipoprotein and lipid-filled macrophages located mainly within the outer plexiform layer .
• Waxy yellow lesions with relatively distinct margins, often arranged in clumps and/or rings at the posterior pole, typically surrounding leaking microaneurysms
• With time number and size tend to increase, and the fovea may be threatened or involved
• When leakage ceases, exudates absorb spontaneously over a period of months or years.
• Chronic leakage leads to enlargement of the exudates and the deposition of cholesterol
Fluorescein angiography shows hypofluorescence due to blockage of background choroidal and retinal capillary fluorescence.