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.
Other things that make a retinal artery occlusion more likely include: Being 40 or older; Being a man; Smoking; Trauma to the eye; Damage from radiation treatments; Kidney disease; Clotting disorders such as sickle cell disease; Birth control pills; Carotid artery disease; Abnormal heart rhythms like atrial fibrillation