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 vascular occlusion affects the eye, specifically the retina. An occlusion occurs when one of the veins or arteries carrying blood to or from the retina becomes blocked or contains a blood clot.The blockage could occur in the main vein or main artery.Blockages could also occur in the branch of veins and arteries throughout the retina.n occlusion occurs when one of the veins or arteries carrying blood to or from the retina becomes blocked or contains a blood clot. The blockage could occur in the main vein or main artery. Blockages could also occur in the branch of veins and arteries throughout the retina.