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.
Blood in the eye from a subconjunctival hemorrhage usually disappears within a week or two. Although it is not always possible to identify the source of the problem, some potential causes of subconjunctival hemorrhage include: Eye trauma can cause a broken blood vessel.