Hard exudates in diabetic retinopathy

In diabetic retinopathy the hard exudates are often arranged in a halo and correspond to a focal oedema. Their number may increase after correctly performed photocoagulation, and may decrease after a certain period. The central (macular) hard exudate may be subretinal and are a poor prognosis, leading to a fibrotic scar. When those exudates are more superficial, filling the cystoid spaces, they are of better prognosis.