Diabetic retinopathy divided by 4 class.
1st , Microaneurysms are the earliest clinical sign of diabetic retinopathy, they appear as small, red dots in the superficial retinal layers.
2nd,Hemorrhage appear similar to microaneurysms if they are small; they occur as microaneurysms rupture in the deeper layers of the retina.
3rd, Exudate caused by the breakdown of the blood-retina barrier, allowing leakage of serum proteins, lipids, and protein from the vessels.
And finally, Cotton-wool spot caused by nerve fiber layer infarctions from occlusion of precapillary arterioles; they are frequently bordered by microaneurysms and vascular hyperpermeability.