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 artery occlusion. Retinal artery occlusion is a blockage in one of the small arteries that carry blood to the retina. The retina is a layer of tissue in the back of the eye that is able to sense light. Causes. Retinal arteries may become blocked when a blood clot or fat deposits get stuck in the arteries.
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.