Webster Dictionary(0.00 / 0 votes)Rate this definition: Freebase(0.00 / 0 votes)Rate this definition: Crenulation or Crenulation cleavage is a texture formed in metamorphic rocks such as phyllite, schist and some gneiss by two or more stress directions resulting in superimposed foliations.
Retinal vein occlusions typically occur in older patients with a history of high blood pressure and atherosclerosis. Other causes of retinal vein occlusion include vasculitis, clotting disorders, and medications such as oral contraceptive pills.
Retinal vasculitis may be complicated by an arteritis, central retinal vein occlusion or central retinal artery occlusion, vitreous haemorrhage and tractional retinal detachment. The prognosis is dependent on the underlying cause, the severity of the vasculitis and the presence/severity of any complications.