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.
Eye Problems and Blood in the Eye. Sometimes small blood vessels in the whites of the eyes break and cause a red spot or speck. This is called a subconjunctival hemorrhage.The blood vessels may break because of sneezing, coughing, vomiting, straining, or bending over, but sometimes there is no clear cause.ometimes small blood vessels in the whites of the eyes break and cause a red spot or speck. This is called a subconjunctival hemorrhage.