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.
Retinal Artery Occlusion. Retinal artery occlusion occurs when the retinal artery or one of its branches becomes blocked. This cuts off the blood and nutrient supply to the nerve layer of the retina, leading to permanent damage. It is a common cause of sudden loss of vision in one eye, which occurs over a few seconds.